IV EVS PA

NOTE UNDERSTAND THE WORKSHEETS THROUGHLY AND THESE ATTEMPT THESE COMPETANCY BASED QUESTIONS  

CHAPTER 8                                         CLASS IV                                             REVISION TEST

Q1.Identify and explain

Look at the farming tools or machinery listed (you may provide images or names in your actual paper).

1. Identify each tool or machine.

2. Describe one practical use for each in farming.

3. Suggest one simple safety or efficiency tip when using any one of them.

Q2.Explain, connect, and evaluate

a) Explain what a weed is and what the practice of weeding involves.
b) Describe how the presence of weeds affects crop growth and yield.
c) Suggest one practical step a farmer or gardener can take to reduce weed impact, and briefly explain why it helps.

Q3.Explain, compare, and evaluate

a) Explain what manure is, how it is made, and how it is used in farming.
b) Compare manure with chemical fertilizers, noting at least one similarity and one difference in their use or effects.
c) Name two examples of chemical fertilizers.

Q4.Explain and infer

a) Discuss whether fertilizers and pesticides can be harmful to humans, and in what ways.
b) Explain what happens when fertilizers or pesticides are washed off by rain—where do they go, and what might be the effect?
c) Propose one measure to reduce such harmful runoff in a local farming or gardening context..

Q5.a) Investigate whether there are pesticides or pest‑control methods that are less harmful to humans. Provide one example or idea.

b) Explain a safe, traditional, or natural way to protect grains or crops from pests—for instance, using neem leaves or another locally available method.
c) Suggest one simple step to test or promote this method in your community or school, mentioning one expected benefit.

Revision test

Class IV

Chapter 9

Q1: What is the first step in the digestive process when food enters the mouth?

(a) It is mixed with digestive juices

(b) It is chewed and ground by teeth

(c) It travels down the food pipe

(d) It is absorbed into the bloodstream

Q2: What role does saliva play in digestion ?

(a) It breaks down proteins

(b) It helps to breakdown food into smaller particles

(c) It absorbs food into the bloodstream

(d) It moves food through the digestive path

Q3: What is the primary function of the small intestine in digestion?

(a) To grind anḍ crush food

(b) To absorb water from the food

(c) To breakdown food into tiny particles and absorb nutrients

(d) To store waste food

Q4: What is the substance in the mouth that helps breakdown starch?

(a) Saliva

(b) Bile

(c) Gastric juice

(d) Pancreatic Juice

Q5: What happens when food passes through the food pipe?

(a) It gets absorbed into the bloodstream

(b) It is churned broken down further

(c) it moves through by muscle contractions

(d) It is digested and absorbed by the stomach.

Q6: Which part of the digestive system is responsible for breaking down food into nutrients that can be absorbed by the body?

(a) Mouth

(b) Stomach

(c) Small Intestine

(d) Large Intestine

Q7: What happens after food is broken down in the small intestine?

(a) It is expelled through the anus .

(b) It is absorbed into the bloodstream.

(c) It moves to the large intestine for digestion

(d) It enters the stomach for further digestion.

Q8: Where is solid waste formed after digestion?

(a) Mouth

(b) Stomach

(c) Small Intestine

(d) Large Intestine

Q9: What does your body do with the food that is absorbed into the bloodstream?

(a) It is converted into waste

(b) It is used to produce energy and maintain growth.

(c) It is stored in the large intestine

(d) It is passed into the stomach for further breakdown

Q10: What does iodine solution do when applied to foods that contain starch?

(a) It turns the food green.

(b) It turns the food black or blue.

(c) It turns the food red.

(d) It makes the food transparent.

Q1.Imagine the stomach were a straight tube instead of its normal bag‑like, expandable shape.

Explain what practical problems or changes in digestion might result. How would this altered shape affect the stomach’s roles such as storing, mixing, or starting to break down food?

Q2.Describe the role of the small intestine in digestion and nutrient absorption.

Show how specific structural features—like its length, folds, or tiny projections—support efficient absorption of nutrients into the body.

Q3.Compare, contrast, and evaluate:

• Compare the main functions of the stomach and the large intestine in the digestive process.

• Contrast how each organ contributes differently to digestion and overall health.

• Decide which of their functions is most critical for nutrition, and justify your choice briefly.

Q4 Compare systems and make a judgement:

Compare the digestive system of a human with that of an earthworm.

• Identify at least two similarities and two differences.

• Decide which system is more complex, and justify your choice based on number of parts, specialization, or processes involved.

Q5.Discuss how the food pipe (oesophagus) supports digestion—and what might happen if it does not work properly.

• Describe its role in moving food toward the stomach.

• Infer probable consequences on digestion or health if the food pipe couldn’t perform this role well.

Revision Test

Chapter 10

Class IV                                                          EVS                                                                       PA 3

Q1. A school eco-club starts a compost pit in the campus. They add vegetable peels, dry leaves, and some earthworms to the pit. After a few weeks, the waste turns into dark, crumbly manure.

(a) Explain how earthworms help in converting garbage into manure.
(b) Predict what would happen if earthworms were not added to the compost pit.
(c) Suggest two benefits of using compost manure in the school garden.

Q2. In your locality, wastewater from houses is carried through underground pipes to a treatment facility before being released into a nearby river.

(a) Identify the different stages that may be involved in treating sewage.
(b) Examine how these treatment methods help in maintaining public health.
(c) Evaluate the environmental benefits of treating sewage before releasing it into water bodies.

Q3. A city plans to build a new Sewage Treatment Plant (STP) because untreated sewage was earlier being discharged into open drains.

(a) Describe the role of a sewage treatment plant in waste management.
(b) Analyze the possible dangers to humans and the environment if sewage is not treated properly.
(c) Suggest two long-term benefits of setting up an STP in the city.

Q4. In a village near a river, some people practice open defecation along the riverbank. After the rainy season, many villagers fall sick due to water-borne diseases.

(a) Explain how improper outdoor defecation affects the environment.
(b) Analyze how it impacts public health.
(c) Justify why defecating near water sources should be strictly avoided.

Q5. A student eats food without washing hands after cleaning a garbage bin and later suffers from stomach infection.

(a) Explain why it is important to wash hands after handling decomposing waste or using the toilet.
(b) Describe the role of microbes in spreading diseases.
(c) Suggest two hygienic practices that can prevent the spread of infections.

Worksheet 1

Multiple Choice Questions:

1. During which stage of rice production are the husks removed?

     (a) Harvesting             (b) Threshing             (c) Miling             (d) Polishing

2. The by-product of rice polishing is often used for:

    (a) Animal feed             (b) Fertilizer             (c) Packaging         (d) Construction material

3. What role do microbes play in decomposing food waste?

    (a) Make food poisonous                     (b) Break down food into simpler substances

    (c) Produce toxic gases                            (d) Increase food weight

4. Why should we wash our hands after handling decomposed food?

    (a) To avoid spreading germs             (b) To remove dirt

    (c) To keep hands dry                         (d) To remove bad smell

5.What is the primary function of a septic tank?

    (a) Store waste permanently                 (b) Break down waste using microbes

    (c) Filter water for reuse                       (d) Incinerate waste

6. What happens to banana peels after they decompose?

    (a) They become fertilizer                     (b) They disappear completely

    (c) They turn into gas                            (d) They remain unchanged

7. Which method is most effective for treating sewage waste?

    (a) Boiling             (b) Filtration             (c) Sewage treatment plant             (d) Direct disposal into rivers

8. Why should outdoor defecation be avoided near water sources?

    (a) It looks unpleasant                            (b) It leads to water contamination

    (c) It causes soil erosion                         (d) It attracts animals

9. Why might covering decomposing food speed up the process?

    (a) It traps heat and moisture                 (b) It prevents flies

    (c) It keeps away sunlight                     (d) It allows ventilation

10. What is the role of bacteria in sewage treatment plants?

    (a) Produces foul smell                         (b) Break down organic waste

    (c) Removes water                                 (d) Solidifies waste

Topic wise assignment class 12 chemistry

 Topic : Raoult’s Law

1. Mixture (s) showing positive deviation from Raoult’s law at 35oC is (are)    JEE Advanced 2016 Paper 2 Offline

(a) carbon tetrachloride + methanol

(b) carbon disulphide + acetone

(c) benzene + toluene

(d) phenol + aniline

Ans : a and b both        

2. The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 g cm–3 . The ratio of the molecular weights of the solute and solvent, , is                          JEE Advanced 2016 Paper 1 Offline

Answer is 9                                            

3. The Henry's law constant for the solubility of N gas in water at 298 K is 1.0  10 atm. The mole fraction of N in air is 0.8. The number of moles of N from air dissolved in 10 moles of water at 298 K and 5 atm pressure is                                            IIT-JEE 2009 Paper 1 Offline

(a) 4.0 x 10-4

(b) 4.0 x 10-5

(c) 5.0 x 10-4

(d) 4.0 x 10-6

Ans: 4.0 x 10-4

4. The vapour pressure of ethanol and methanol are 44.5 and 88.7 mm Hg respectively. An ideal solution is formed at the same temperature by mixing 60 g of ethanol with 40 g of methanol. Calculate the total vapour pressure of the solution and the mole fraction of methanol in the vapour.                                                                                        IIT-JEE 1986

Answer is 66.17 mm, 0.65

Topic : Elevation in Boiling Point

1. Consider the following aqueous solutions.                           JEE Main 2026 (Online) 28th January Evening Shift

I. 2.2 g Glucose in 125 mL of solution.

II. 1.9 g Calcium chloride in 250 mL of solution.

III. 9.0 g Urea in 500 mL of solution.

IV. 20.5 g Aluminium sulphate in 750 mL of solution.

The correct increasing order of boiling point of these solutions will be :

[Given : Molar mass in g mol−1 : H = 1, C = 12, N = 14, O = 16, Cl = 35.5, Ca = 40, Al = 27 and S = 32]

(a) III < I < II < IV

(b) II < III < IV < I

(c) II < III < I < IV

(d) I < II < III < IV

Ans : I < II < III < IV\

2. A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol−1) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is ______ × 10−2. (nearest integer)

[Given: Kb of the solvent = 5.0 K kg mol−1]

Assume the solution to be dilute and no association or dissociation of X takes place in solution.                                                                JEE Main 2026 (Online) 21st January Evening Shift

Ans: 3

3. Elements P and Q form two types of non-volatile, non-ionizable compounds PQ and . When 1 g of  is dissolved in 50 g of solvent '  was 1.176 K while when 1 g of  is dissolved in 50 g of solvent '  was 0.689 K . ( Kb of 'A` = 5 K kg/mol). The molar masses of elements P and Q (in g/mol ) respectively, are :                                                JEE Main 2026 (Online) 21st January Morning Shift

(a)  25,60     (b) 60,25     (c) 65,145     (d) 70,110

Ans: (a) 25,60 

4. 2 moles each of ethylene glycol and glucose are dissolved in 500 g of water. The boiling point of the resulting solution is: (Given : Ebullioscopic constant of water is 0.52 K kg/mol) 

(a) 377.3 K    (b) 379.2 K     (c) 375.3 K    (d) 277.3 K        JEE Main 2025 (Online) 3rd April Morning Shift

Ans: (a) 377.3 K 

5. When 1 g each of compounds AB and AB2 are dissolved in 15 g of water separately, they increased the boiling point of water by 2.7 K and 1.5 K respectively. The atomic mass of A (in amu ) is_________  (Nearest integer)                                

JEE Main 2025 (Online) 2nd April Evening Shift

(Given : Molal boiling point elevation constant is  )

Ans: 2.5

6. 1.24 g of AX2 (molar mass 124 g mol−1) is dissolved in 1 kg of water to form a solution with boiling point of 100.015°C, while 25.4 g of AY2 (molar mass 250 g mol−1) in 2 kg of water constitutes a solution with a boiling point of 100.0260°C.

Kb(H2O) = 0.52 kg mol−1

Which of the following is correct?                                JEE Main 2025 (Online) 29th January Morning Shift

(a) AX2 and AY2 (both) are completely unionised.

(b) AX2 and AY2 (both) are fully ionised.

(c) AX2 is completely unionised while AY2 is fully ionised.

(d) AX2 is fully ionised while AY2 is completely unionised.

Ans: (d) AX2 is fully ionised while AY2 is completely unionised.

7. Arrange the following solutions in order of their increasing boiling points.

(i) 10-4 M NaCl

(ii) 10-4 M Urea

(iii) 10-3 M NaCl

(iv) 10-2 M NaCl                                        JEE Main 2025 (Online) 22nd January Morning Shift

(a) i<ii<iii< iv

(b) ii < i < iii < iv

(c) iv < iii < i < ii

(d) ii < i = iii <iv

8. A solution containing 10g of an electrolyte AB2 in 100 g of water boils at100.52 C. The degree of ionization of the electrolyte 

 is _________ . (nearest integer)

[Given : Molar mass of  (molal boiling point elevation const. of water) , boiling point of water  ionises as

AB2 --> A2+ + 2B-                                                              JEE Main 2024 (Online) 8th April Morning Shift

Answer = 5

9.  2.5g of a non-volatile, non-electrolyte is dissolved in 100g of water at 25 C. The solution showed a boiling point elevation by 2 C. Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is _________ mm of Hg (nearest integer)                            JEE Main 2024 (Online) 4th April Morning Shift

[Given : Molal boiling point elevation constant of water ,  pressure  of , molar mass of water 

Ans : the vapor pressure of the aqueous solution is 707 mm Hg.

10. A solution of two miscible liquids showing negative deviation from Raoult's law will have

(a) increased vapour pressure, increased boiling point

(b) increased vapour pressure, decreased boiling point

(c) decreased vapour pressure, decreased boiling point

(d) decreased vapour pressure, increased boiling point         JEE Main 2024 (Online) 27th January Morning Shift

Ans:  (d) decreased vapour pressure, increased boiling point

11. Sea water contains  and  by weight of solution. The normal boiling point of the sea water is _____________  (Nearest integer)

Assume  ionization for both  and 

Given : 

Molar mass of  and  is 58.5 and 95  respectively.

Ans: 116 C

12. If the boiling points of two solvents X and Y (having same molecular weights) are in the ratio  and their enthalpy of vaporizations are in the ratio , then the boiling point elevation constant of  is  times the boiling point elevation constant of Y. The value of m is ____________ (nearest integer)

Ans : 8

13. The vapour pressure vs. temperature curve for a solution solvent system is shown below.

The boiling point of the solvent is __________ .

Ans : 82

14. A solution containing 2g  of a non-volatile solute in 20 g of water boils at 373.52 K . The molecular mass of the solute is ___________ g/mol.

Given, water boils at 373 K, Kb for water is 0.52 K Kg/mol  .

Ans : 100

15. Boiling point of a  aqueous solution of a non-volatile solute A is equal to the boiling point of  aqueous solution of a non-volatile solute B. The relation between molecular weights of A and B is

(a) MA= 4MB

(b) MB = 4MA

(c) MA= 8MB

(d) MB = 8MA

Ans : (b) MB = 4MA

16. A solution containing 2.5  103 kg of a solute dissolved in 75  103 kg of water boils at 373.535 K. The molar mass of the solute is ____________ g mol1. [nearest integer] (Given : Kb(H2O) = 0.52 K kg mol1 and boiling point of water = 373.15 K)

Topic : Depression in Freezing Point

1. On dissolving 0.5 g of a non-volatile non-ionic solute to 39 g of benzene, its vapor pressure decreases from 650 mmHg to 640 mmHg. The depression of freezing point of benzene (in K) upon addition of the solute is .............

(Given data: Molar mass and the molal freezing point depression constant of benzene are 78 g mol-1 and 5.12 K kg mol-1, respectively).                                JEE Advanced 2019 Paper 1 Offline

Answer = 1.02

2. Pure water freezes at   and  bar. The addition of   of ethanol to   of water changes the freezing point of the solution. Use the freezing point depression constant of water as  kg  The figures shown below represent plots of vapor pressure  versus temperature  [molecular weight of ethanol is    ] Among the following, the option representing change in the freezing point is                    JEE Advanced 2017 Paper 2 Offline

(a) 

(b) 

(c) 

(d) 

3.If the freezing point of a 0.01 molal aqueous solution of a cobalt (III) chloride-ammonia complex(which behaves as a strong electrolyte) is – 0.0558oC, the number of chloride(s) in the coordination sphere of the complex is [Kf of water = 1.86 K kg mol–1 ]        

Answer = 1                                                                                JEE Advanced 2015 Paper 1 Offline

4. Properties such as boiling point, freezing point and vapour pressure of a pure solvent change when solute molecules are added to get homogeneous solution. These are called colligative properties. Applications of colligative properties are very useful in day-to-day life. One of its examples is the use of ethylene glycol and water mixture as anti-freezing liquid in the radiator of automobiles.

A solution M is prepared by mixing ethanol and water. The mole fraction of ethanol in the mixture is 0.9.

Given:

Freezing point depression constant of water  K kg mol

Freezing point depression constant of ethanol  K kg mol

Boiling point elevation constant of water  K kg mol

Boiling point elevation constant of ethanol  K kg mol

Standard freezing point of water = 273 K

Standard freezing point of ethanol = 155.7 K

Standard boiling point of water = 373 K

Standard boiling point of ethanol = 351.5 K

Vapour pressure of pure water = 32.8 mm Hg

Vapour pressure of pure water = 40 mm Hg

Molecular weight of water = 18 g mol

Molecular weight of ethanol = 46 g mol

In answering the following questions, consider the solutions to be ideal dilute solutions and solutes to be non-volatile and non-dissociative.                           IIT-JEE 2008 Paper 1 Offline

The freezing point of the solution M is :

(a) 268.7 K            (b) 268.5 K        (c) 234.2 K            (d) 150.9 K

Answer = (d) 150.9 K

5. 75.2 g of C6H5OH (phenol) is dissolved in a solvent of Kf = 14. If the depression in freezing point is 7 K then find the % of phenol that dimerises.                            IIT-JEE 2006

Answer = 75

6. A solution of a nonvolatile solute in water freezes at -0.30oC. The vapour pressure of pure water at 298 K s 23.51 mm Hg and Kf for water is 1.86 K kg mol-1. Calculate the vapour pressure of this solution at 298 K.                                                          IIT-JEE 1998

Answer is 23.44 mm Hg

7. The freezing point of equimolal aqueous solutions will be highest for        IIT-JEE 1990

(a) C6H5NH3Cl (aniline hydrochloride)

(b)  Ca(NO3)2

    (c) La(NO3)3

      (d) C6H12O6 (glucose)

Answer : (d) C6H12O6 (glucose)