Grade 6th Science
Holidays homework:-
Learn chapter 1,2 ,3 and 4 for UT
Do assignment in separate notebook.
Do activities
Chapter 1 "Food: Where does it come from"
1. Draw fig 1.4 Different edible parts of plants.
2. Complete table 1.5 Animals and their food (write in notebook)
Chapter 2"Components of food"
1. Write the test for Proteins , fats and starch.
2. Dietary fibres are important to us. Why?
3. Learn and write table 2.3 some diseases/ disorders caused by deficiency of vitamins and minerals.
Chapter 3"Fibre to Fabric"
1. What are natural fibres? Give two examples.
2. What is ginning?
Chapter 4"Sorting Materials into groups"
1. Write three water soluble and 3 water insoluble substances .
2. Write three hard and three soft substances
3. Write three objects that float in water and three objects that sink in water.
4. Write three transparent , Translucent and opaque objects.
Activity :-
Grow 4 plants in your Terris . Write about their botanical name , habitat , morphology and economic importance points .
Make a video to describe them .
Activity:-
Why do we need to protect house sparrow ?
Make a video to describe them .
Getting to know about plants
Assignment :
Define the following :
Herbs , Shrubs ,Trees , node, internode , stomata, transpiration
Ans : Herbs:-Plants with green and tender stems are called herbs For example: mint (Pudhina), rosemary, coriander (Dhaniya), bay leaf (Tejpatta), basil (Tulsi).
Shrubs:-Some plants have stem branching out near the base there stem is hard but not too thick these are called shrubs. Example :- Hibiscus
Trees:-Some plants are very tall and have hard and thick brown stem. The stem has branches in the upper part, much above the ground. Such plants are called trees.
For Example: Apple tree, Mango tree, Neem tree, Coconut tree, Oak tree etc
Node : The point from where a leaf grows is called node.
Internode: The portion of stem between two consecutive nodes is called internode.
Stomata: The tiny openings in the lowest layer of leaves . It helps the plants for gaseous exchange.
Transpiration:-Water vapors are released into the atmosphere through stomata present on leaf this process is called transpiration.
Differentiate between creepers and climbers .
Creepers : plants having weak stems thet spread on the ground and cannot stand upright are called creepers. Ex: mint and gourd.
Differentiate Annual, Biennial and Perennial Plants.
Annual:The plants whose life cycle , from seed germination to the fruit formation , is completed in one season are called annual plants.These are generally herbs. Examples : Wheat, Paddy , Mustard , Moong , gram, petunia and Balsam .
Biennial:The plants whose life cycle requires two seasons for completion are called biennial plants. For example, Carrots , Radish, Potato, Tulip Etc.
Perennial Plants:The plants whose life cycle requires more than two seasons for completion are called Perennial plants.. Examples Neem, guava , Jamun ,Etc.
Draw a well labeled diagram of a plant showing two systems : root system and shoot system.
What do you mean by root system ? Explain its types with example .
The non green part of plant that remains and grows underground is called root system. Root develops from the radicle of the seed and grow towards soil and water .
Types of root : two types
!. Tap root : Tap root is the main root from which many branching roots grow sideways . ex: tulsi, mustard etc.
2. Fibrous root : A cluster of thin fibre like roots at the base of the stem is called fibrous root. Ex: Wheat, maize, grass etc.
What do you mean by shoot system ? What does it consist of ?
The portion of plants above the ground is called the shoot system . It consists of main stem, its branches , leaves , flowers and fruits .
Write the three functions of following : Roots , Stem , Leaves and flower.
Three functions of Roots :
Hold the plant firmly in the soil .
Absorb water and minerals from the soil
Prevent soil erosion .
Three functions of Stem :
Conduction of water and minerals from soil to outer parts of plants
Conduction of food made by leaves
Provide physical support to branches, leaves , flowers and fruits .
Three functions of Leaves 👍
Perform photosynthesis .
Helps in transpiration
Helps in respiration
Three functions of flower.
Ovary of flower develops into fruits. Its ovules form the seeds .
Flowers are the source of perfumes , flavouring foods and certain medicines.
Nectar from flowers is used by honey bees to prepare honey.
Define venation and its types . .
Arrangement of veins and veinlets in the leaf blade is called venation .
Parallel Venation:-If the design made by veins is parallel to one another in a leaf is called parallel venation. For example: grass, wheat, maize etc
Reticulate venation:-If the design is net like on both sides of midrib is called reticulate venation. For example: coriander, rose, oak etc.
Draw a reticulate leaf and mention
(i) the site of photosynthesis, ( leaf blade )
(iI) part which transport water and minerals (mid rib and veins )
Draw a well labelled diagram of flower.
Chapter 9 : "The Living Organisms and their Surroundings"
Q1. Write three main habitats in the biosphere. Give examples of each.
Q2. Explain two components of habitat. Give examples of each.
Q3. What is adaptation?
Q4. Explain hibernation. Give one example.
Q5. Why is a camel called ‘the ship of the desert’?
Q6. What are Xerophytes and succulent plants?
Q7. Write adaptations of the following:-
desert plants (b) mountain trees and plants © mountain animals
(d) aquatic animals (e) aquatic plants
Q8. Define excretion. Name two products excreted by trees.
Q9. Define reproduction.Write two ways by which different animals reproduce.
Chapter 10: Motion and its measurements
Q1. What does each measurement consist of?
Q2. Mohan’s house is 6750 metres from his school. Express this distance in kilometres.
Q3. Write the SI unit of length. Name some devices used to measure length.
Q4. When an object is said to be in motion?
Q5. Explain in detail with examples
Rectilinear motion
Circular motion
Rotatory motion
Periodic motion
Q6. Match the following:-
COLUMN A COLUMN B
Handspan (1) linear motion
1km (2) rotatory motion
Car moving on a straight road (3) periodic motion
Motion of a spinning top (4) 1000m
Moving needle of sewing machine (5) length
Chapter 11 Electricity and Circuits
Ques 1: What do you mean by dry cell?
Ques 2: How much voltage is provided by dry cell?
Ques 3: What is the use of dry cell ?
Ques 4: What does dry cell consist of?
Ques 5 Write three advantages of dry cell.
Ques 6:bWhat do you mean by solar cell ? write its uses.
Ques 7: Define electric circuit.
Ques 8: Why does a fused bulb not glow?
Ques 9: Draw the symbols for following electric components .
Cell , battery, lamp , Connecting wire , open key, closed key.
Ques 10 Define Conductors and insulators with example.
Ques 11:Draw an electric circuit with bulb, key, battery and connecting wires.
Ques 12: What are button cells? Write most commonly used button cells.
Chapter 12 Light
ASSIGNMENT
Q1. Define luminous and non-luminous objects.Give examples of each.
Q2. ‘Moon shines at night,but it is a non luminous body’.Explain .
Q3. Classify the materials on the basis of their behaviour towards light.Explain them in detail with examples.
Q4. Write any three characteristics of a shadow.
Q5. Write the materials needed to show the formation of a shadow.
Q6. Differentiate between the image and the shadow of an object.
Q7. Write advantages and disadvantages of a pinhole camera.
Q8 Define a mirror.
Q9 Define reflection, incident ray and reflected ray.
Q10. Draw a diagram showing reflection of light rays by a plane mirror.
Q11. Fill in the blanks:-
Light travels at a speed of ________.
_______ is a natural luminous body.
_______ and ________ are man made luminous bodies.
The shadow formed of a red apple is of _________ colour.
Light always travels in ________line .
Grade 7th science
Chapter 1,2,3 and 6 prepare for U.T (keywords+ back exercise+ Ques Ans + assignment+ diagrams)
Chapter 1 "Nutrition in plants"
1. How do water and minerals transported to the leaves?
2. Name the food factory of plants.
3. Draw a section through a leaf and stomata.
4. Draw diagram showing photosynthesis
5. How do plant get nitrogen?
6. Do leaves other than green also make their food themselves? How?
7. How does pitcher plant get moisture from insects?
8. What is symbiosis relationship?
Chapter 2 " Nutrition in animals"
1. Complete the table 2.1 in separate notebook.
2. Draw human digestive system.
3. Draw digestive system of ruminant
4. Draw the diagram of Amoeba.
5. Name the two sets of teeth come in humans.
6. Discuss in detail about digestion in humans.
Chapter 3 " Fibre to Fabric"
1. Name two animals that yield wool
2. Write in detail about the life history of silk moth.
Chapter 4 "Heat"
1. A clinical thermometer reads temperature from ___ °C to ___ °C
2. What precautions to be observed while reading a clinical thermometer?
3. The normal temperature of human body is ___°C .
4. The range of a laboratory Thermometer is generally from ___°C to ____°C
5. What precautions to be observed while reading a laboratory thermometer?
6. What is sea breeze?
7. What is land breeze?
Chapter 6 " Physical and Chemical changes"
Identify A to H
1. Magnesium (Mg) + Oxygen (O2) --> A
2. Magnesium oxide (MgO) + water (H2O) ------->B
3. Copper sulphate solution(blue) + iron --> C +D
4. Vinegar (Acetic acid) + Baking soda (Sodium hydrogencarbonate) --> E + F
5. Carbon dioxide[CO2]+Lime water --> G + H
6. What are the observation that may accompany a chemical change?
Activity :-
Grow 4 plants in your Terris . Write about their botanical name , habitat , morphology and economic importance points .
Make a video to describe them .
Activity:-
Why do we need to protect house sparrow ?
Make a video to describe them .
Grade 8th
Learn chapter 1,2,8 and 11 for U.T
Do this assignment in separate notebook.
Chapter 1 "Crop production and management"
1. Write difference between fertilizer and manure
2. Write the advantages of manure.
3. What is drip irrigation system?
Chapter 2 " Microorganisms: Friend and For"
1. Draw fig 2.1(Bacteria) ,2.2(Algae), 2.3(Protozoa), 2.4(Fungi) , 2.5 (virus)
2. Write and learn table 2.1 Some common human diseases caused by Microorganisms.
3. Write and learn table 2.2 "some common plants diseases caused by microMicroorga"
4. Draw the nitrogen cycle.
5. Name two nitrogen fixers.
Chapter 3 " Synthetic Fibres and Plastics"
1. Write 2 uses for each
- Rayon
-Nylon
-polyester and Acrylic.
2. Write the charactersticha of plastics .
3 .Write a short note on plastics and the environment
Chapter 8"Cell - Structure and Functions"
1. Write the difference between unicellular and multicellular organisms.
2 draw fig 8.4 (a) spherical red blood vells,
(b) spindle shaped muscle cells , (c) Long branched nerve cell
3. Write a short note on nucleus.
4. Write difference between prokaryotes and eukaryotes.
5. Draw plant cell and animal cell.
Chapter 11"Force and pressure"
1. What can a force do?
2. Force can change the state of motion. How?
Activity :-
Grow 4 plants in your Terris . Write about their botanical name , habitat , morphology and economic importance points .
Make a video to describe them .
Activity:-
Why do we need to protect house sparrow ?
Make a video to describe them .
Grade IX
Chapter 1 "Matter in our surroundings"
QUESTION 1. Differentiate between Solid,Liquid and Gas.
QUESTION 2: Define Matter, latent heat of fusion , Latent heat of vaporisation, Sublimation, condensation, evaporation
QUESTION 3 Difference between evaporation and Boiling.
QUESTION 4 On what factors rate of evaporatioin depends?
QUESTION 5 How does evaporation cause cooling? Illustrate with three examples.
QUESTION 6 Why do we prefer cotton clothes in summer?
Chapter 2 "Is Matter Around Us Pure"
QUESTION 1: How is physical and chemical change differ to each other?
Question 2: What is solution? When is it called saturated solution?
Question 3 What do you mean by dispersive phase and dispersive medium?
Question 4: Enlist the properties of solutions.
Question 5 : Differentiate between Homogeneous and Heterogeneous mixture.
Question 6: Write the properties of colloids and suspension.
Chapter 3 : Atoms and Molecules
Ques 1Define Atoms and Molecules .
Ques 2 State Law of Conservation of mass .
Ques 3 State aw of constant proportion .
Ques 4 Write the postulates of Dalton atomic theory .
Ques 5 Write the symbolic representation of the following : Magnesium oxide , Zinc oxide , aluminium sulphate, copper nitrate , Quick lime , slaked lime , Nitric acid , Sulphuric acid, Baking Powder .
Ques 6 What is the molar mass of CO2 , H2O, NH3
Chapter 5"The fundamental unit of life"
Chapter 8 "Motion"
Numerical:-
1. An athlete covers one round of a circular track of diameter 200 m in 40 second. What will be the distance covered and the displacement at the end of 2 min 20 second?
2. Usha swims in a 90m long pool . She covers 180m
3. Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 50 seconds and then turns around and jogs 100m back to point C in another 1 minute. What are Joseph's average speeds and velocities in jogging.
(a) from A to B and
(b) from A to C
4. The odometer of a car reads 200 km at the start of a trip took 8hours . Calculate the average speed of car in Km/Hr and m/s
5. Abdul while driving to school , computes the average speed for his trip to be 20km/hr . On his return trip along the same route, there is less traffic and the average speed is 40km/he . What is the average speed for Abdul's trip.
6. A bus decrease it's speed from 80 Km/he to 60km/Hr in 5 second. Find acceleration of the bus.
7. A train starting from a railway station and moving with uniform acceleration attains a speed of 40km/hr in 10 minutes. Find its acceleration.
8. Starting from a stationary position, Rahul paddles his bicycle to attain a velovvel of 6m/s in 30 second. Then he alpliap brakes such that the velocity of bicycle comes down to 4m/s in next 5 second. CalciCalc the acceleration of bicycle in both cases.
9. The speed time graph for a car is shown in fig :-
(a) find how far does the car travel in the first 4 seconds.
Shade the area on the graph that represents the distance travelled by the car during the period
(b) which part of the graph represents uniform motion of the car?
10. A bus starting from rest moves with a uniform acceleration of 0.1 m/s^2 for 2 minutes.
Find (a) speed acquired and (b) distance travelled
11. A train is travelled at a speed of 90km/Hr . Breaks are applied so as to produce a uniform acceleration of -0.5 m/s^2 . Find how far the train will go before it is brought to rest.
12. A trolley while going down an inclined plane has an acceleration of 2 cm/s^2 . What will be it's velocity 3s after the start.
13. A racing car has a uniform acceleration of 4 m/s ^2 . What distance will it cover in 10 sec after start?
14. A stone is thrown in a vertically upward direction with a velocity of 5m/s . If the acceleration of the stone during its motion is 10m/s^2 in downward direction, what will be the height attained by stone and how much time will it take to reach there?
15. A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m/s^2 for 8 sec . How far does boat travel during the time?
16. A ball is gently dropped from a height of 20 m . If it's velocity increase uniformly at the rate of 10 m/s^2 , with what velocity will it strikes the ground? After what time will it strikes the ground?
17. Derive all the three equations of motion.
Science project draw on A3 size sheet
1.draw a compound microscope
2. Draw various cells from the human body
3. Draw animal cell
4. Draw plant cell
5. Draw meiosis and mitosis
Grade 10
1. Make a project according to roll number
a.) Make a chart of modern periodic table (on page no 86).
b.) A cross section of leaf on A3 size sheet (on page no 96)
c.) Open and closed stomatal pore on A3 size sheet (on page no. 97)
(d) Nutrition in Amoeba on A3 size sheet (on page no 98)
(e) Human alimentary canal on A3 size sheet (on page no. 99)
(f) Human respiratory system on A3 size sheet (from notes)
(g) Human heart on A3 size sheet (on page no. 106)
(h) Human excretory system on A3 size sheet (on page no. 110)
(I) structure of a nephron on A3 sheet (on page no 111)
(J) structure of neuron, neuromuscular junction on A3 size sheet (on page no 115)
(K) Reflex arc on A3 size sheet (on page no 117)
(L) Human brain on A3 size sheet (on page mo.118)
(m) longitudinal section of flower on A3 size sheet (on page no. 134)
(n) Germination of pollen grain on stigma on A3 size sheet (on page no 135)
(o) Ray diagrams for the image formation by a concave mirror on chart (on page no 166)
(p) formation of image by a convex mirror on A3 size sheet (on page no 167)
(q) The position , size and the nature of the image formed by a convex lens for various positions of the object on chart (on page no. 181)
(r) Nature, position and relative size of th image formed by concabc mirror on A3 size sheet (on page no 181)
(s) the human eye on A3 size sheet (on page no 187)
Do these assignments in separate notebook
Learn them properly
Chapter 1 " Chemical Reactions and equations"
1. Classify the following reactions into different types:
(i) AgNO3(aq) + NaCl (aq) --> AgCl (s) + NaNO3(aq)
(ii)CaO (s) + H2O (l) --> Ca(OH)2(aq)
(iii) 2KClO3(s) + heat --> 2KCl (aq)) + 3O2(g)
(iV) An + CuSO4 --> ZnSO4 + Cu
2. Translate the following statement into a balanced chemical equation:-
"Barium chloride reacts with aluminium sulphate to give aluminium chloride and barium sulphate."
3. When potassium iodide solution is added to a solution of lead nitrate in a test tube , a precipitate is formed.
(a) What is the colour of this precipitate? Name the compound precipitated.
(b) Write the balanced chemical equation for this reaction.
(c) List two types of reactions in which this reaction can be placed.
4. A white powder is used by doctors to support fractured bones.
(a) Write the name and chemical formula of the powder.
(b) how is this powder prepared?
(c) When this white powder is mixed with water, a hard solid mass is obtained. Write a balanced chemical equation for the change.
(d) Give one more use of this white powder.
5. A student mixes sodium sulphate powder in barium chloride . What change would the student observe on mixing the two powder . Justify your answer and explain how he can obtain the desired change.
6. Write balanced chemical equations for the following reactions?
(i) dilute sulphuric acid reacts with aluminium powder.
Ans:- H2SO4 + Al ---> Al2(SO4)3 + H2
(ii) dilute hydrochloric acid reacts with sodium carbonate.
Ans:- HCl + Na2CO3 --> NaCl + H2O + CO2
(iii) Carbon dioxide is passed through like water.
Ans:- Ca(OH)2 + CO2 --> CaCO3 + H2O
7. 1 g of copper power was taken in a China dish and heated. What change takes place on heating? When hydrogen is passed over this heated substance a visible change is seen in it. Give the chemical equations of reactions.
Ans:- Cu +O2 +heat --> CuO
CuO + H2---> Cu + H2O
8. Read the given passage and answer any four questions.
The physical states of the reactants and products can be represented by using the symbols, (s) for solids, (l) for liquids , (g) for gases and (aq) for aqueous solution along with their respective formulae. The word aqueous is written if the reactant and product is present as a solution in water. Precipitate can also be represented by using an arrow pointing downwards instead of using symbols (s)
In the same way , the gaseous state of an evolved gas can be represented by using an arrow pointing upward direction instead of using symbol (g) . The specific condition of the reaction like temperature, pressure, catalyst etc. Is written above or below the arrow in the chemical equation.
(a) write balanced chemical equation with state symbols
Magnesium reacting with Dil sulphuric acid
Ans:- Mg (s) + H2SO4 (dil) (aq) --> MgSO4 (s) + H2(g)
(b) To indicate the presence of gaseous reactant or product, we use ____ symbol
Ans:- (g) or upward arrow
(c) write X and Y in the following reaction:-
2Na(s) + 2H2O(l) --> 2NaOH (X) + H2(Y)
Ans :- X=(aq) and Y= (g)
(d) which of the following reaction is balanced?
(i) 2NaCl + 2H2O --> 2NaOH + 2Cl2 +H2
(ii) Ca(OH)2 + Cl2 --> CaOCl2 + H2O
(iii) NH3 --> N2+ H2
(iv) C6H12O6 + O2 --> CO2 +H2O
Ans (ii)
(e) It is necessary to balance a chemical equation in order to satisfy the law of ______
Ans :- conservation of mass
9. Write balanced chemical equations for the following reactions:-
(I) Dil sulphuric acid reacts with aluminium powder.
Ans:- Al (s) + H2SO4 (aq) --> Al2(SO4)3(aq) + H2(g)
(ii) dilute hydrochloric acid reacts with sodium carbonate
Ans:- Na2CO3 (s) + HCl (aq) --> NaCl (aq) + CO2 (g)+ H2O(g)
(iii) carbon dioxide is passed through lime water.
Ans:- Ca(OH)2 + CO2--> CaCO3 + H2O
10). 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolved which is bubbled through a salt solution before testing . Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the metal reacts with dilute solution of a strong acid?
Ans:- NaOH (aq)+ Zn(s) --> Na2ZnO2 +H2
Detection of gas :- pop up sounds will be produced in soap solution. The gas will be H2 gas.
When the metal react with Dil solution of strong acid then also it will evolve H2 gas.
Chapter 4 "Carbon and it's componds"
Ques 1:- Define catenation
Ques 2:- The formulae of four organic compounds are given below :
A = C2H4 ; B = CH3COOH ; C = C2H5OH ; D = C2H6
(I) Which of these compounds is a saturated hydrocarbon?
(ii) Identify the organic acid and it's structural formula.
(iii) Which of the above compounds when heated at 443K in the presence of concentrated H2SO4 forms ethene as the major product? What is the role played by concentrated H2SO4 in this reaction? Also write the chemical equation involved.
Ques 3:- Conversion of ethanol to ethanoic acid is an oxidation reaction. Justify this statement giving the relevant equation for the chemical reaction involved.
Ques 4:- Write the name and molecular formula of carbon compounds having its name suffixed with -ol and having two carbon atoms in its molecule. With the help of a chemical equation indicate what happens when this compound is heated with excess conc. H2SO4
Ques 5:- Distinguish between esterification and saponification reactions with the help of chemical equations for each.
Ques 6:- What happens when 5% alkaline potassium permanganate solution is added drop by drop to warm propyl alcohol taken in a test tube? Explain with the help of chemical equation.
Ques 7:- Write the structural formulae for
(I) 2-Methylbut-2-ene (II) 2-Methylpropene
(iii) 3,3,3-trichloropropanal (IV) 2-Methylbutanal (v) 3,3-Dimethylbut-1-ene
Ques 8:- An organic compound X of molecular formula C2H6O reacts with K2Cr2O7 and H2SO4 and forms an acidic compound Y. The compound X reacts with Y in the presence of concentrated H2SO4 and heated the releases a sweet smelling substance Z . Identify X,Y and Z
Ques 9 Ankura class 10 student starts to a chapter carbon and it's componds. While studying the chapter he got a doubt. Next day , he went to his teacher and asked him that ,"Why carbon can neither form C4+ cation nor C4- anionbut for. Covalent componds? What explanation is given by teacher?
Ques 10:- mark the correct answer.
(a) If both assertion and reason are correct and reason is the correct explanation of assertion.
(b) If both assertion and Reason are true, but reason is not correct explanation of Assertion
(c) If assertion is true ,but reason is false
(d) If assertion is false , but reason is true.f
Assertion :- n-pentane, iso-pentane and neo-pentane are structural isomers of each other.
Reason:- Structural isomers have the same molecular formula but differ in their structures.
Chapter 6 " Life processes"
1. Single circulation, I.e blood flow through the heart occuring only once during a complete cycle of blood passage throughout the body, is exhibited by
(a) Label, Chameleon, Salamander
(b) Hippocampus, Exocoetus, Anabas
(c) Hyla, Rana , Draco
(d) Whale, Dolphin, Turtle
2. Coagulation of blood in a cut or wound is brought about by ____
3. While breathing out, point out the changes you think occur in diaphragm and intercostal muscles.
4. Write the function of the following in the human alimentary canal.
(i) saliva (ii) HCl in stomach
(iii) Bile juice (iV) villi
5.write one function each of the following enzymes (i) Pepsin (ii) Lipase.
6. Draw a diagram of human excretory system and label the following
(i) urinary bladder (ii) left kidney (iii) left ureter.
Chapter 10 " Light - Reflection and Refraction"
1. The magnification produced by a plane mirror is +1 . What does it mean?
2. How will the image formed by a convex lens be affected, if the lower half of the lens is covered with black paper?
(a) The lower half of the image will be absent
(b) The size of image is reduced to one half.
(c) The brightness of the image is reduced
(d) There will be no effect
3.Power of the plane mirror is
(a) infinity (b) zero (c) negative (d) positive
4. What is the nature of the image formed by a concave mirror, if the magnification produced by the mirror is -0.75?
5.A bus uses a convex mirror as view finder whose radius of curvature is 4m. A car is coming behind the bus , which is at a distance of 20m . What will be the position and size of the image of the car when observed by the driver of the bus through the convex mirror?
6. Calculate the distance at which an object should be placed in front of a concave lens of focal length 30cm to obtain an image of half of its size.
7 State laws of Reflection of light
8. Define absolute refractive index and express it mathametically.
chapter 15 "Our Environment"
1. Draw a food chain that exists in a terriestrial ecosystem.
2. In the food chain you have drawn , identify the organisms which act as primary and secondary consumers in this exosystem
3. What will be the amount of energy available to third trophic level if plants have 20,000 J of energy.
4. The process of accumulation of harmful chemicals like DDt through the food chain each trophic level is known as____
5. Replacing of plastic cups by the paper cups for selling tea and coffee on train and bus is preferred because
(a) paper cups are cheaper
(b) paper cups are more hygienic
(c) paper cups are more aesthetic
(d) paper cups are biodegradable and eco-friendly
6. Natural water bodies are not regularly cleaned whereas an aquarium needs regular cleaning. Why?
7. What are decomposers? What will be the consequences if the decomposers are completely eradicated from an ecosystem? Give justification in support of your answer.
8. How is ozone formed in the upper atmosphere? State its importance . What is responsible for its depletion? Write one harmful effect of ozone depletion.
9. Accumulation of harmful chemicals in our bodies can be avoided . Explain how this can be achieved?
Ans :- Now a days, we are using insecticides and pesticides at large amount . These things don't digested in our body. So at every meal these things gets accumulated . This can be harmful in our bodies. To avoid this it is mendatory that we prefer organic farming and try to get fruits and vegetables by our own kitchen garden and use manure for their cultivation.
Grade 12th (hbse)
Chapter 1
1. Ionic solids conducts electricity in molten state but not in solid state. Explain.
2. What is the significance of a lattice point?
3. Differentiate between crystalline and amorphous solids
Chapter 2 "Solutions"
Assignment 1.
Topic 1. Types , Concentration terms and Solubility of solution.
One mark ques-answer:-
Give reason for the following .
Aquatic animals are more comfortable in cold water than in warm water.
Define the term mole fraction.
Explain the Henry`s about dissolution of a gas in a liquid.
State the main advantage of molality over molarity as the unit of concentration.
2 marks Questions
State Henry`s law . Calculate the solubility of CO2 in water at 298K under 760 mm Hg (KH for CO2 in water at 298 K is 1.25 x 106 mm Hg).
Give reasons for the following .
aquatic species are more comfortable in cold water than warm water.
At higher altitudes people suffer from anoxia resulting in inability to think.
Define the following terms : (i) Mole fraction (ii) Molality of a solution.
Calculate the molarity of 9.8% solution of h2so4 if the density of the solution is 1.02 g ml-1 [molar mass of H2SO4 = 98 g/mol]
Differentiate between molarity and molality of a solution .How can we change molality value of a solution into molarity value?
A solution of glucose in water is labelled as 10% by weight . What would be the molality of the solution ?(Molar mass of glucose is 1780 g/mol.
If the density of water of a lake is 1.25 g/ml and 1 Kg of lake water contains 92g of Na+ ions , Calculate the molarity of the molarity of Na+ ions in this lake water .(Atomic mass of Na = 23 g/mol)
Differentiate between molarity and molality for a solution . How does a change in temperature influence their values ?
Explain why aquatic species are more comfortable in cold water rather than in warm water.
State Henry`s law and mention its two important applications
3 marks questions
A solution of glucose (molar mass= 180 g/mol) in water is labelled as 10% (by mass) . What would be the molarity of the solution ? (Density of solution = 1.2 g/mol)
The partial pressure of ethane over a saturated solution containing 6.56 x 10-2 g of ethane is 1 bar . If the solution contains5.0 x 10-2 g of ethane , then what will be the partial pressure of the gas?
If N2 gas is bubbled through water at 293 K , how many millimoles of N2 gas would dissolve in 1 L of water ? Assume that N2 exerts a partial pressure of 0.987 bar . Given that Henry`s law constant for N2 at 293 K bar is 76.48 K bar.
Assignment 2
Topic:- Vapour pressure of liquid Solutions, Ideal and Non- ideal Solutions
1 Marks Questions :
Define an ideal solution and write one of its characteristics .
Some Liquids on mixing form azeotropes. What are azeotropes?
State Raoult`s law for a solution of volatile liquids..
What is the similarity between Raoult`s law and Henry`s law?
2 marks Questions :
What type of azeotropic mixture will be formed by a solution of acetone and chloroform? Justify on the basis of strength of intermolecular interactions that develop in the solution.
State Raoult`s law for a solution containing volatile components Writ two characteristics of the solution which obeys Raoult`s law at all concentrations.
Write two differences between an ideal and non ideal solution.
Why a mixture of carbon disulphide and acetone shows positive deviation from Raoult`s law? What type of azeotrope is formed by this mixture?
Define the following .
A gas (A) is more soluble in water than gas (B) at the same temperature . Which one of the two gases will have the higher value of KH and why?
IN non-ideal solution , What type of deviation shows the formation of maximum boiling azeotropes?
What is meant by negative deviation from Raoult`s law? Give an example . What Is the sign of ΔmixH for negative deviation?
What is meant by positive deviation from Raoult`s law? Give an example . What Is the sign of ΔmixH for negative deviation?
Define Azeotropes. What type of azeotropes is formed by negative and postitive deviation from Raoult`s law? Give an example.
3 marks Questions:
The vapour pressure of pure liquids A and B are 450mm and 700 mm of Hg respectively at 350K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm of Hg. Also , Find the composition in the vapour phase.
Assignment 3a
Topic : Colligative Properties and van`t Hoff factor
1 marks questions
What are isotonic solutions?
Define the term Osmotic pressure and osmosis
What is meant by reverse osmosis?
Explain boiling point elevation constant for a solvent or ebullioscopic constant.
2 marks questions
5. What happens when,
(I) a pressure greater than osmotic pressure is applied on the solution side separated from solvent by a semipermeable membrane?
(II) acetone is added to pure ethanol?
6. Calculate the freezing point of a solution containing 60 g of glucose in 250 g of water.
(Molar Mass = 180 g/mol). (Kf of water = 1.86 K Kg/mol)
7.Give reasons for the following :
(I) Measurement of osmotic pressure method is preferred for the determination of molar masses of macromolecules such as proteins and polymers.
(II) Elevation of boiling point of 1 M KCl solution is nearly double than that of 1M sugar solution.
8. Define the following terms :
(I) Coligative properties
(II) Molality
9. Define the following terms:
(I) Abnormal molar mass
(II) Van`t hoff factor
(iii) Isotonic solutions
10. How is the osmotic pressure related to the concentration of a solute in a solution?
11. (i) On mixing liquid X and liquid Y , volume of the resulting solution decreases. What type of deviation from Raoult`s law is shown by the resulting solution? What change in temperature would you observe after mixing liquids X and Y?
(II) what happen when w placed blood cell in water (hypertonic solution) ? Give reason.
12. Why does a solution containing non-volatile solute have higher boiling point than the pure solvent ? Why is elevation of boiling point a colligative property?
13. Calculate the mass of compound (molar mass =256g/mol) to be dissolved in 75 g of benzene to lower its freezing point by 0.48 K (Kf = 5.12 K kg/mol)
14. How is the vapour pressure of a solvent affected when a non-volatile solute is dissolved in it?
15. An aqueous solution of sodium chloride freezes below 273 K . Explain the lowering in freezing point of water with the help of suitable diagram.
16. 18 g glucose, is dissolved in 1 kg of water in a sauce pan . At what temperature , will this solution boil? (Kb for water=0.52 Kkg/mol , boiling point of pure water = 373.15K)
17. A 1.00 molal aqueous solution of trichloroacetic acid (CCl3COOH) is heated to its boiling point . The solution has the boiling point 100.18 ͦC. Determine the van`t Hoff factor for trichloroacetic acid. (Kb for water = 0.512 K kg/mol)
18.Is the osmotic pressure related to the concentration of a solute in a solution? Explain.
19.What possible values can van`t Hoff factor have if the solute molecuiles undergo dissociation?
20.The molecular masses of polymers are determined by osmotic pressure method and not by measuring other colligative properties. Give two reasons.
21. What is the advantage of using osmotic pressure as compared to other colligative properties for determination of molar masses of solutes in solutions?
22. Find the boiling point of a solution containing 0.520 g glucose dissolved in 80.2 g of water (given ,Kb for awter = 1.86 K/m)
23. Find the freezing point of a solution containing 0.520 g glucose dissolved in 80.2 g of water (given ,Kf for water = 1.86 K/m )
24. Outer hard shells of two eggs are removed . One of the eggs is placed in pure water and the other is placed in saturated solution of sodium chloride. What will be observed and why?
3 marks questions :
25. A 0.01 m aqueous solution of AlCl3 freezes at -0.068°C .Calculate the % of dissociation. (Given : Kf for water = 1.86 Kkg/mol)
26. The freezing point of a solution containing 5g benzoic acid (M= 122g/mol) in 35 g of benzene is depressed by 2.94 K. What is the % of association?(Kf for benzene = 4.9 K kg/mol)
27.At 300K , 30g of glucose present in a litre of its solution has an osmotic pressure of 4.98 bar. If the osmotic pressure of a glucose solution is 1.52 bar at the same temperature , what wouls be its concentration?
28. A 4% solution (w/w) of sucrose (M= 342 g/mol) in water has a freezing point of 271.15 K. Calculate the freezing point of 5% glucose (Molar mass =180g/mol) in water. (Given : Freezing point of pure water = 273.15 K )
29. Calculate the freezing point of an aqueous solution containing 10.5 g of magnesium bromide in 200 g of water, assuming complete dissociation of magnesium bromide .(Molar mass of Magnesium bromide = 184g/mol , Kf for water = 1.86 K kg/mol)
30. A 10% solution (by mass ) of sucrose in water has freezing point of 269.15 K. Calculate the freezing point of 269.15 K. Calculate the freezing point of 10% glucose in water, if freezing point of pure water is 273.15 K.(given molar mass of sucrose = 342 g/mol and molar mass of glucose = 180 g/mol)
d and f Block Elements
a. Transition metals and their compounds show catalytic activities.Give reason.
b. Write the formula of an oxo-anion of manganese (MN) in which it shows the oxidation state equal to its group number.
c. Zn2+ salts are white , while Cu2+ salts are coloured. Why?
d. Why do transition elements show variable oxidation states?
e. Transition metals are much harder than the alkali metals. Why?
f. Which of following cations are coloured in aqueous solutions and why?
Sc3+ , V3+, Ti4+ , Mn2+
g. Sc(21) is a transition element but Ca(20) is not . Why?
h. Explain the following observations :
Most of the transition metals ions exhibit characteristics colours in aqueous solutions.
i. How would you account for the following: Many of the transition elements are known to form transition compounds.
j. Copper (I) ion is not known in aqueous solution. Give reason.
k. Cr2+ is a strong reducing agent, whereas Mn3+ with the same (d4) configuration Is an oxidising agent . Give reason.
l. Ti3+ is coloured, whereas Sc3+ is colourless in aqueous solution.
m. Cr2+ Is a strong reducing agent.
n. Write the balanced ionic equations showing the oxidising action of acidified dichromate (Cr2O7 2-) solutions with (i) iron (II) ion and (ii) tin(II) ion.
Or
Cr2O7 2- + Fe2+ -->
Cr2+O7 2- + Sn2+ -->
o. When MnO2 is fused with KOH in the presence of KNO3 as an oxidising agent, it give a dark green compound (A) . Compound (A) disproportionates in acidic solution to give purple compound (B) . An alkaline solution of compound (B) oxidises KI to compound (C) , whereas an acidified solution of compound (B) oxidises KI to (D) . Identify (A),(B),(C) and (D) .
Or
Describe the preparation of KMnO4.
p. When chromite ore, FeCr2O4 is fused with NaOH in the presence of air , a yellow coloured compound (A) is obtained, which on acidification with dilute sulphuric acid gives a compound (B) . Compound (B) on reaction with KCl forms an orange coloured crystalline compound (C)
(i) Write the formulae of the compounds (A) ,(B) and (C)
(ii) Write the use of compound (C)
Or
Describe the oxidising action of K2Cr2O7.
q. What are transition elements? Write two characteristics of the transition elements.
r. What is meant by 'disproportionation'? Give an example of a disproportionation reaction in aqueous solution.
s. Suggest reasons for the following features of transition metal Chemistry:
(i) The transition metal and their compounds are usually paramagnetic.
(ii) The transition metals exhibit variable oxidation states.
t. Why do transition elements show variable oxidation states? In 3d series (SC to Zn) , which element shows the maximum number of oxidation states and why?
u. Assign a reason for each of the following observations:
(i) The transition metals (with the exception of Zn, Cd and Hg) are hard and have high melting and boiling points.
(ii) The ionisation enthalpies (first and second) in the first series of the transition elements are found to vary irregular.
v. Assign reason for each of the following:
(i)Transition elements exhibit paramagnetic behaviour.
(ii)Co^2+ is easily oxidised in the presence of a strong ligand
w.Account for the following:
(i) Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
(ii) The enthalpy of atomisation is lowest for zinc in first series (3d) of the transition elements.
x. Describe the general trends in the following properties of the first series (3d) of the transition elements
(i) Number of oxidation states exhibited.
(ii) Formation Oxo metal ions.
y. Assign reasons for the following :
(i) Copper (I) ion is not known to exist in aqueous solutions.
(ii) Transition metals and many of their compounds act as good catalysts.
(iii) Transition metals generally form coloured compounds.
z. How would you account for the following:
(i). The highest oxidation states of a transition metal is usually exhibited in its oxide.
2 marks question
(a) How would you account for the following:
The oxidising power of the following three oxo-ions in the series follows the order :
VO2^+ < Cr2O7^-2-<MnO4^-1
(ii) There is hardly any increase in atomic size with increasing atomic numbers in a series of transition metals.
(iii) Manganese exhibits the highest oxidation state of +7 among the 3d series of transition elements.
(iv) Zinc is not regarded as a transition element.
(v) Among the divalent cations in the first series of transition elements, manganese exhibits the maximum paramagnetism.
(vi) Zn, Cd and Hg are soft and have low melting points.
(vii) E° values for Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+
(viii) Transition metals forms complex compounds.
(ix) The Mn2+ compounds are more stable than Fe2+ towards oxidation to their +3 state.
(x) Mn(III) undergoes disproportionation reaction easily.
(xi) Compare the stability of +2 oxidation state for the elements of the first transition series .
(xii) The lowest oxide of a transition metal is basic, the highest is amphoteric or acidic .
(xiii) Cobalt (II) is stable in aqueous solution but in the presence of complexing agents , it is easily oxidised.
(xiv) Which element has the highest melting point?
(xv) Which element shows only +3 oxidation state?
(xvi) Which element is a strong oxidising agent in +3 oxidation state and why?
(xvii) The highest oxidation states are usually exhibited by the members in the middle of a series of transition elements.
(xviii) A transition metal exhibits higher oxidation states in oxides and fluorides.
(XIX) Cr2+ is a stronger reducing agents than Fe2+
(XX) Name the Oxo metal anion of one of the transition metals in the metal exhibits the oxidation state equal to the group number.
b. Which metal in the first transition series exhibits +1 oxidation state most frequently and why?
c. Complete the following ionic equations :-
(i) MnO4^-2 + 4H+ -->
(ii) Fe2+ + MnO4^-1 + H+ -->
(iii) MnO4^-1 + H2O + I^-1 -->
(iv) MnO4^-1 + S2O3^2- + H2O -->
(v) Cr2O7^2- + Sn2+ + 14H+ -->
(vi) MnO4^-1 + S^2- + 16H+ -->
(vii) Cr2O7^2- + 2OH-1 -->
(viii) MnO4^-1 + NO2^-1 + H+ -->
(Ix) MnO4^-1 + C2O4^2- + H+ -->
(x) MnO2 +KOH + O2 -->
(xi) I^-1 + MnO4^-1 +H+ -->
(x) KMnO4 + heat -->
(xi) CrO4^2- + H+ -->
(XII) MnO4- + SO3^2- + H+ -->
Coordination compounds:-
One marks Ques ans:-
1. What is the difference between a complex and a double salt?
2. Write the coordination isomer of [Cu(NH3)4][PtCl4].
3. Write the coordination number and oxidation state of platinum in the complex [Pt(en)2Cl2].
4. Write down the IUPAC name of the complex , what type of isomerism is shown by this complex and draw their structures
(i)Pt(en)2Cl2]2+ (draw geometrical isomers) (ii) [Ni(NH3)6]Cl2
(iii) [Co(NH3)5SO4]Cl? (iv) [Co(NH3)6][Cr(CN)6]
(v) K3[CrF6] (vi) [PtCl(NH2CH3)(NH3)2]Cl
(vii) [Pt(NH3)4Cl2]Cl2 (VIII) [Cr(NH3)6][Co(CN)6]
(ix)[Pt(NH3)(NO)Cl2]Br2 (x) [Co(CN)2(NH3)4]Cl
(xi) [Cr(NH3)5(NCS)][ZnCl4] (xii) [Co(NH3)Cl]Cl2
(xiii) [Cr(NH3)4Cl2]+ (xiv) [Cr(en)3]Cl3
(xv) [Cr(NH3)4Cl2]+ (xvi) [Co(NH3)4(H2O)Cl]Cl2
(xvii) [CrCl2(en)2]Cl (xviii) [Ni(NH3)6]Cl2
(xix) K3[Fe(CN6)] (xx) [Co(en)3]3+
(xxi) [NiCl4]2-
5. Define denticity of ligands.
6. What is ambidentate ligand? Give an example.
7. Give an example of coordination isomerism.
8. Give an example of ionisation isomerism
9. Differenciate between an ambidentate ligand and a chelating ligand.
10. Using IUPAC name , write the formula for the following :
(i) Potassium trioxalatoaluminate(III)
(ii) Hexaaminecobalt(III) sulphate
(iii) Potassium trioxalatochromate(III)
(iv) Dichloridobis(ethane-1,2-diamine)cobalt (III) ion
(v) Sodium dicyanidoaurate(I)
(vi) Tetraamminechloridonitrito-N-platinum (IV) sulphate
(vii) Potassium tetrachloridonickelate (II)
(viii) Pentaaminenitrito-o-cobalt (III) ion
(ix) Potassiumtrioxalatochromate (III) ion
(a) When a coordination compound CrCl3.6H2O is mixed with AgNO3 2 moles of AgCl are precipitated per mole of the compound . Write structural formula of the complex.
(b)When a coordination compound CoCl3.6NH3 is mixed with AgNO3 , 3 moles of AgCl are precipitated per mole of the compound. Write structural formula of the complex.
(c) Why CO is a strong ligand than Cl-. ?
Ans:- Ligand such as CO hs empty π orbitals which overlab with the filled d orbitals (t2g ) of the transition metals forming π bonds(back bonding)
Hence CO is a π acceptor ligand which can accept the electron density from the metal atombinto their π or π* orbitals. These π interactions increases the value of ∆o . Thus CO is a strong field ligand.
(d) What do you mean by chelate effect?
(d) What is meant by crystal field splitting enenrgy? How does the magnitude of splitting decide the actual configuration of d-orbitals in an octahedral field for a coordination entity?
(e) Deccribe the shape and magnitic behaviour of [Ni(CN)4]2- .
(f) Explain the following terms :
-crystal field splitting in an octahedral field
- Spectrochemical series
(g) Using VBT , deduce the magnetic character of [Co(NH3)6]3+ ion.
(h) Out of [CoF6]3- and [Co(en)3]3+ , which one complex is (i) paramagnetic (ii) more stable(iii) inner orbital complex and (iv) high spin complex.
(I) What is the state of hybridisation , the shape and the magnetic behaviour of the following complex entities.
- [Cr(NH3)4Cl2]Cl
-[Co(en)3]Cl3
Haloalkaneand haloarene
1.Write the structure of following:
- 2,4-Dinitrochlorebenzene,
- 1-bromo-4-chlorobut-2-ene,
- 3-bromo-2-methylprop-1-ene
- 1,4-dibromobut-2-ene
- 2-(2-bromopheny)butane
- 2-(2-chlorophenyl)-1-iodoctane
- 1-bromo-4-sec-butyl-2-methylbenzene
- 2-chloro-3-methylpentane,
- 3-(4-chlorophenyl)-2-methylpropane
- 4-tert-butyl-3-iodoheptane
- 1-chloro-4-ethylcyclohexane
- 4-bromo-3-methylpent-2-ene
- 4-bromochlorbenzene
3. Write the mechanism of the following reaction:
CH3CH2OH +HBr--> CH3CH2Br +H2O
4. Out ofCH3CH2CH2Cl and CH2=CH-CH2-Cl , which one is morereactive towards SN1 reaction.
5.Why is t-butyl bromide more reactive towards SN1 reaction as compared to n-butylbromide.
6. Predict the major product formed
Alcohols ,Phenols and Ethers
One marks Questions:-
1.Which of the following isomers is more volatile :o-nitrophenol or p-nitrophenol?
2. How is toluene obtained from from phenol ?
3. o-nitrophenol has lower boiling point than p-nitrophenol. Explain.
4. How would you obtain ethane-1,2-diol from ethanol?
5. Draw the structure of hex-1-en-3-ol compound, 2,6-dimethylphenol.
6. The C-O bond is much shorter in phenol than in ethanol. Give reason.
7. How could you convert ethanol to ethene?
8. Write Reiman Tiemann reaction by giving an example.
9. Write the chemical equation for the preparation of phenol from benzene using oleum and sodium hydroxide.
10.Write the mechanism of acid dehydration of ethanol to yield ethene.
11. Write the equation involved in the reaction:- Williamson's synthesis.
12. Explain the following by giving one example . Friedel Crafts acetylation of anisole.
13. Phenyl methyl ether reacts with HI to give phenol and methyl iodide and not iodobenzene and methyl alcohol. Why?
14. Write Kolbe's reaction with an example.
15 Write friedel Crafts alkylation of phenol.
Two marks Questions:-
1. Write the mechanism of the following SN1 reaction ,
(CH3)3C-Br + aq NaOH -->(CH3)3C-OH +NaBr
2. Arrange the following compounds in the increasing order of the property indicated .Also give reason.
(a) p-cresol, p-nitrophenol, phenol (acidic strength)
(b) p-nitrophenol, ethanol, phenol (acidic strength)
(c) Propanol ,propane, propanol (boiling point)
3. How will you convert the following ?
(i) Propan-2-ol to propanone
(ii) Phenol to 2,4,6- tribromophenol
(iii) propene to propan-1-ol
(iv) ethanal to propan-2-ol
(v) propene to propan-2-ol
(vi) phenol to2,4,6- trinitrophenol
(vii) phenol to picric acid
(Viii) 2-methyl propene to 2-methyl propanol
(ix) Benzyl chloride to Benzyl alcohol
(X) Methyl magnesium bromide to 2-methylpropan-2-ol
(xi) propene to propan-2-ol
(XII) Ethyl magnesium chloride to propan-1-ol
(xiii) phenol to benzoquinone
(xiv) methanal to ethanol
(xv) phenol to o-hydroxybenzaldehyde
(xvi) Phenol to phenyl ethanoate
(xvii) ethanol to ethoxy ethane
(xvii) propan-1-ol to1-propoxy propane
(xviii) phenol to benzene
(XIX) propene to propan-2-ol
(XX) ethanol to ethanal
(XXI) Butanal to Butanol
(XXII) Primary alcohol to aldehyde
(XXIII) Phenol to anisole
(XXIV) Aniline to phenol
(XXV) Propan-2-ol to 2-methylpropan-2-ol
(XXVI) Anisole to p+bromoanisole
4. Write the mechanism of :-
(a)hydration of ethene to ethanol.
(b) acidic hydrolysis of ethanol to ethene
(c) acidic hydrolysis of ethanol to ethoxy ethane
(d) ethanol to bromoethane
(e) Phenol to Anisole
(f) ethanol to propan-2-ol
5. Give one chemical test to distinguish between the following pairs of compounds .
(a) Phenol and benzoic acid
(b) 1-propanol and 2-propanol
(c) ethanol and phenol
(d) Propanol and 2-methylpropan-2-ol
6. Explain the following behaviours:-
(a) alcohols are more soluble in water than the hydrocarbons of comparable molecular masses
(b) ortho-nitrophenol is more acidic than ortho-methoxyphenol
(c) Propanol has higher boiling point than butane
(d) boiling points of alcohols decrease with increase in branching of the alkyl chain
(e) Phenol does not give protonation reaction readily.
(f) boiling point of ethanol is higher than that of methanol
(g) Phenol is a stronger acid than an alcohol
(h)Phenol undergoes electrophilic substitution more easily than benzene.
(i) The C-O-H bond angle in alcohols is slightly less than the tetrahedral angle(109°28')
7. Assertion and Reason
Directions : In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct answer out of the following choices.
(a) Both A and R are correct; R is the correct explanation of A.
(b) Both A and R are correct; R is not the correct explanation of A.
(c) A is correct; R is incorrect.
(d) A is incorrect; R is correct.
(1)Assertion (A) IUPAC name of the compound
CH-CH(CH3)-O-CH2-CH2-CH, is 1-(2-propoxy) propane
Reason (R) In IUPAC nomenclature, ether is regarded as hydrocarbon derivative in which a hydrogen atom is replaced by -OR [where, R-alkyl group].
2 Assertion (A) The bond angle in alcohol is slightly more than the tetrahedral angle.
Reason (R) Variation in bond angle of alcohol is due to the repulsion between the unshared electron pair of oxygen.
3. Assertion (A) Carbon oxygen bond length of phenol is slightly less than that of methanol.
Reason (R) There exist a partial double bond character and sp2-hybridisation of carbon to which oxygen is attached in phenol
4 Assertion (A) The C-O bond length (141 pm) of ether is almost same as in alcohols. Reason (R) The bond angle in ether is slightly greater than the tetrahedral angle due to repulsive interaction between the two bulky (-R) groups.
5 Assertion (A) Commercially acids are reduced to alcohols by converting them to the esters followed by their reduction using catalytic hydrogenation.
Reason (R) LIAIH4,can reduce carboxylic acids to primary alcohols but LiAlH4, is an expensive reagent and used for preparing special chemicals only.
6 Assertion (A) In alcohols, the boiling point decreases with decrease in the branching of the carbon chain.
Reason (R) There is the decrease in van der Waals forces between the number of carbon atoms with decrease in the surface area in alcohols
7 Assertion (A) Lower alcohols and phenols are soluble in water.
Reason (R) There occurs a dipole-dipole interaction of -OHgroup of alcohol and phenol with water molecules, which is responsible for their solubility in water.
8 Assertion (A) An alcohol is more volatile than anether having the same molecular formula
Reason (R) Intermolecular hydrogen bonding exist in alcohols
9 Assertion (A) Dipole moment of phenol is smaller than that of methanol.
Reason (R) In phenol C-O bond is less polar, whereas in methanol, C-O bond is more polar
10 Assertion (A) Increasing order of acid strength of alcohol is 1° alcohol>2° alcohol>3° alcohol
Reason (R) An electron releasing group increases the electron density on oxygen which tends to decrease the polarity of O-H bond.
11 Assertion (A) Alcohols act as Lewis bases. Reason (R) It is due to the presence of shared electron pairs on oxygen which make them proton donors.
12 Assertion (A) CH3OH and CH3CH2OH can be distinguished by haloform test reaction.
Reason (R) Haloform test is given by 2° alcohol.
13 Assertion (A) Oxidation of alcohols is also known as dehydrogenation reaction.
Reason (R) There is the gain of dihydrogen from an alcohol molecule during oxidation.
14 Assertion (A) Methanol poisoned patients are prone to blindness and death.
Reason (R) In body, methanol is oxidised first to methanoic acid and then to methanal which may cause blindness and death.
15 Assertion (A) o-nitrophenol is less volatile than p-nitrophenol.
Reason (R) There occur intramolecular hydrogen bonding in o-nitrophenol and intermolecular hydrogen bonding in p-nitrophenol.
16 Assertion (A) Bromination of phenol takes place even in the absence of Lewis acid.
Reason (R) In phenol, -OH group attached to benzene ring has highly deactivating effect.
17 Assertion (A) In the presence of air, phenol mixture becomes dark in colour.
Reason (R) Phenols are slowly oxidised to the dark coloured mixture containing quinones.
18 Assertion (A) Alcohols do not react with NaBr but when H2SO4 is added they form alkyl bromide
Reason (R) Water act as a good leaving group.
19.Assertion (A) Phenol reacts with CH3I in presence of NaOH to form methoxybenzene.
Reason (R) Phenoxide is better nucleophile than phenol.
20 Assertion (A) Ethers are not obtained during the dehydration of secondary and tertiary alcohols.
Reason (R) In the secondary and tertiary alcohols, elimination competes over substitution during dehydration.
21 Assertion (A) Diethyl ether has been replaced as an anaesthetic by other compounds.
Reason (R) Diethyl ether is highly expensive.
22 Assertion (A) 7.5 g of ethoxyethane and 9 g of butan-1-ol is miscible to almost same extent while pentane is essentially immiscible with water.
Reason (R) Alcohols and ethers can form hydrogen bonds with the water molecule.
23 Assertion (A) The cleavage of C-O bond in ethers take place under drastic condition with excess of hydrogen halides.
Reason (R) Ethers are the most reactive among all the functional groups.
8.Case Study
(Read the passage given below and answer the following questions)
Case I Phenols contain a hydroxy (-OH) group directly attached to the aromatic ring. A hydroxy group attached to an aromatic ring is usually referred to as a phenolic group. Due to the presence of -OH group, phenols show many reactions similar to those of alcohols. However, the direct attachment of -OH group to the aromatic ring makes its behaviour very much different from that in alcohols. This is why phenols behave differently from alcohols in many respect. The chemical reactions of phenols can be categorised as follows:
(A) Reactions involving-OH group.
(B) Reactions involving the aromatic benzene ring.
1. In preparation of phenol using oleum and sodium hydroxide, write the starting material to complete the reaction.
(a) benzene (b) toluene (c) Anisole (d) cresol
2. What is the final product when Phenol reacts with Br2/CS2 at low temperature?
(a) o-bromophenol and o-bromophenol
(b) meta bromophenol and bromoethane
(c) p-bromophenol and p-bromoanisole
(d) o-bromophenol and bromophenylmethane
3. Which compound renders violet colour to the reaction of phenol with FeCl3?
(a) Penta-phenoxy ferrate (III)
(b) Hexa-phenoxy ferrate (III)
(c) Hepta-phenoxy-ferrate (III) (d) Penta-phenoxy ferrate (II)
4. Why p-cresol is insoluble in water and dilute HCl?
(a) Because p-cresol is strong base
(b) Because p-cresol is weak acid
(c) Because p-cresol is strong acid
(d) Because p-cresol is weak base
Or
What product will be obtained, when phenol first reacts with conc. H2SO4, and then with conc. HNO3?
(a) o-nitrophenol (b) p-nitrophenol
(c) m-nitrophenol (d) o-cresol
Case II Ethers are quite stable compounds. These do not easily react with dilute mineral acids, alkalis, oxidants, reductants and active metals under ordinary conditions.
Some important chemical properties of ethers are
I. Reactions of alkyl group
When an ether is treated with chlorine in dark, chlorination preferentially occurs at a-carbon and as a result 1, 1'- dichlorodiethyl ether is formed
II. Reactions of the ethereal oxygen
On account of the presence of two lone pairs of electrons on oxygen, ethers behave as Lewis bases and undergo reactions involving the formation of coordinate bonds through the oxygen atoms of ethers.
III. Reactions involving the cleavage of C-O bond
When ethers are heated with halogen acids, phosphorus pentachloride, sulphuric acid, etc. then C-O bond in ethers breaks to give the product.
(Read the above passage and answer the following questions).
1. What happens when diethyl ether is exposed to air and light for a long time?
2. How ether can be freed from peroxides?
3. In absence of kerosene oil can we store sodium in diethyl ether or ethyl alcohol or anhydrous hexanol?
4. Complete and balance the following chemical equation: CHOC2H5 + Cl2 +Sunlight →...+HCI
Or
Write the name of the product when tert. butyl methyl ether is heated with conc. H₂SO4
BEd
Child growth and development 2021
Compulsory Ques. (4*4=16)
1. Differentiate between growth and development
2.characteristics of play
3. Educational implications of Kohlberg theory
4. Parenting style
Unit I (16 marks each)
2. Define growth and development. Discuss various factors affecting growth and development
3. Adolescent age is a period of stress and storm. Justify the statement with the help of examples.
Unit II
4. Describe in detail about various stages of Erickson theory of social and emotional development along with its implications in the field of education.
5. Explain the concept of cognitive development. Discuss the implications of Piaget's theory of cognitive development with reference to Indian context.
Unit III
6. Explain the role of family as an agency of socialisation in child development with the help of suitable examples.
7.What are social and cultural changes? Discuss their impact on the development of children.
Unit IV
8. Discuss the concept of marginalization.with special reference to social class and poverty.
9. Explain stereotyping . Discuss the role of stereotyping on the development of children with special reference to India
Child growth and development 2022
Compulsory Ques
1. Concept of human growth
2. Concept of parenting style
3. Meaning of marginalization.
4. Concept of socio-emotional development.
Unit I
2. Discuss the principles of growth and development.
3. Explain the need and problems of adolescent with special reference to India.
Unit 2
4. What are the stages of development according to Piaget's theory of cognitive development?
5. What are the salient features of Kohlberg theory of moral development along with its implications in Indian context.
Unit 3
6. Define socialisation. Discuss the role of school and community in child development.
7. Discuss the implications of social and cultural changes on the development of child.
Unit 4
8. What is the role of media in influencing people perceptions on contemporary issues ? Explain.
9. How do marginalization and stereotyping influence the child's development? Discuss with example.
