Organic chemistry test

Class XI Chemistry*

 Multiple Choice Questions (Each question carries 1 mark)

1. The IUPAC name of (CH₃)₂CHCH₂CH(CH₃)₂ is:

A) 2,4-Dimethylpentane                            B) 3,3-Dimethylpentane

C) 2,3-Dimethylpentane                            D) 3,4-Dimethylpentane

2.The correct IUPAC name of the compound CH₃CH=C(CH₃)₂ is:

A) 2-Methyl-2-butene                                B) 3-Methyl-2-butene

C) 2,2-Dimethylpropene                            D) Isobutene

3. The IUPAC name of the compound (CH₃)₂C=CHCH₃ is:

A) 2-Methyl-2-butene                                B) 3-Methyl-1-butene            

C) 2,3-Dimethylbutene                               D) 3-Methyl-2-butene

4. The IUPAC name of CH₃CH₂C(CH₃)₂CH₂CH₃ is:

A) 3,3-Dimethylpentane                            B) 2,2-Dimethylpentane

C) 2,3-Dimethylpentane                            D) 3,4-Dimethylpentane

5.The IUPAC name of (CH₃)₃CCH₂CH₂OH is:

A) 3,3-Dimethylpropan-1-ol            B) 2,2-Dimethylpropan-1-ol

C) 3,3-Dimethylbutan-1-ol                D) 2,2-Dimethylbutan-1-ol

6. The IUPAC name of CH₃CH(CH₃)CH₂COCH₃ is:

A) 4-Methyl-2-pentanone                B) 3-Methyl-2-pentanone

C) 2-Methyl-3-pentanone                D) 4-Methyl-3-pentanone

7. The correct IUPAC name for (CH₃)₃CCH₂COOH is:

A) 3,3-Dimethylbutanoic acid                B) 2,2-Dimethylbutanoic acid

C) 3,3-Dimethylpentanoic acid                D) 2,2-Dimethylpentanoic acid

8.The IUPAC name of the compound with structure CH₃COCH₂CH₂CHO is:

A) 4-Oxopentanal            B) 5-Oxopentanal            C) 2-Oxopentanal            D) 3-Oxopentanal

9. The IUPAC name of (CH₃)₂CHCH=CHCHO is:

A) 4-Methylpent-2-enal                    B) 3-Methylpent-2-enal            

C) 3-Methylpent-3-enal                    D) 2-Methylpent-2-enal

10.The IUPAC name of CH₃CH(OH)CH(CH₃)₂ is:

A) 3-Methyl-2-butanol                            B) 2-Methyl-2-butanol

C) 2-Methyl-3-butanol                            D) 3-Methyl-3-butanol

11. The IUPAC name of CH₃CH(Br)CH₂CH₃ is:

A) 2-Bromobutane            B) 3-Bromobutane            C) 1-Bromobutane        D) tert-Butyl bromide

12.The IUPAC name of (CH₃CH₂)₂O is:

A) Ethoxyethane            B) Diethyl ether                C) Ethoxy methane        D) Dimethyl ether

13.The correct IUPAC name for CH₃CH=C(CH₃)CH₂CH₃ is:

A) 3-Methylpent-2-ene                    B) 4-Methylpent-2-ene

C) 2-Methylpent-2-ene                    D) 3-Methylpent-1-ene

14.The IUPAC name of CH₃CH₂CH=CHCN is:

A) Pent-3-enenitrile        B) Pent-2-enenitrile        C) But-2-enenitrile            D) But-3-enenitrile

15.The correct IUPAC name of (CH₃)₂CHCH₂CH₂COOH is:

A) 3-Methylpentanoic acid            B) 2-Methylhexanoic acid

C) 4-Methylhexanoic acid            D) 2-Methylpentanoic acid

16.The IUPAC name of (CH₃CH₂)₃CBr is:

A) tert-Butyl bromide                                    B) 1-Bromo-3-methylbutane

C) 1-Bromo-2,2-dimethylpropane                D) 2-Bromo-2,3-dimethylbutane

17.The IUPAC name of CH₃CH=C(CH₃)CH₂CH₂CH₃ is:

A) 3-Methylhex-2-ene        B) 2-Methylhex-2-ene

C) 3-Methylhex-1-ene            D) 2-Methylhex-3-ene

18.The compound CH₃CH=C(CH₃)CH=CH₂ is named as:

A) 2,4-Dimethyl-1,3-pentadiene            B) 2-Methyl-1,3-pentadiene

C) 3-Methyl-1,4-pentadiene                    D) 2,3-Dimethyl-1,4-pentadiene

19.The IUPAC name of C₆H₅CH=CHCOOH is:

A) 3-Phenylpropanoic acid        B) Cinnamic acid

C) 2-Phenylethanoic acid            D) 2-Phenylpropanoic acid

20.The IUPAC name of (CH₃)₃CCH₂COCH₃ is:

A) 3,3-Dimethyl-2-butanone        B) 4,4-Dimethyl-2-pentanone

C) 3,3-Dimethyl-2-pentanone        D) 4,4-Dimethyl-3-pentanone

Multiple Choice Questions (Each question carries 1 mark)

1. The IUPAC name of C₆H₅CH₃ is:

A) Phenylmethane    B) Methylbenzene    C) Toluene    D) Benzylmethane

2. The IUPAC name of o-dichlorobenzene is:

A) 1,2-Dichlorobenzene        B) 1,3-Dichlorobenzene

C) 1,4-Dichlorobenzene        D) Benzene dichloride

3. The compound C₆H₅NO₂ is named as:

A) Phenyl nitrite        B) Nitrobenzene        C) Aminobenzene        D) Benzenamine

4. The IUPAC name of benzene with an –OH group is:

A) Benzyl alcohol        B) Phenol            C) Hydroxybenzene        D) Benzenol

5. The IUPAC name of C₆H₅NH₂ is:

A) Aniline              B) Aminobenzene    C) Benzenamine            D) All of the above

6. The IUPAC name of CH₃C₆H₄NO₂ (p-isomer) is:

A) 4-Nitrotoluene    B) 2-Nitrotoluene    C) 3-Nitrotoluene    D) p-Methyl nitrobenzene

7. The IUPAC name of CH₃C₆H₄OH (o-isomer) is:

A) 1-Methyl-2-hydroxybenzene    B) 2-Methylphenol    C) o-Cresol    D) All of these

8. The compound C₆H₅COOH is called:

A) Phenol        B) Benzoic acid        C) Benzaldehyde        D) Benzyl alcohol

9. The IUPAC name of C₆H₅CHO is:

A) Benzene carboxaldehyde        B) Benzaldehyde        C) Phenylmethanal    D) Both B and C

10. The IUPAC name of C₆H₅CH₂OH is:

A) Benzyl alcohol            B) Phenylmethanol               C) Both A and B        D) Phenol

11. The compound with formula (CH₃)₂CHC₆H₅ is:

A) Isopropylbenzene        B) Cumene                       C) 2-Phenylpropane            D) All of the above

12.The IUPAC name of CH₃C₆H₄CHO (p-isomer) is:

A) 4-Methylbenzaldehyde            B) 2-Methylbenzaldehyde

C) 3-Methylbenzaldehyde            D) p-Methylbenzaldehyde

13.The IUPAC name of the compound CH₃C₆H₄COOH (m-isomer) is:

A) 3-Methylbenzoic acid            B) 4-Methylbenzoic acid

C) 2-Methylbenzoic acid            D) m-Methylbenzoic acid

14.The IUPAC name of C₆H₅CH₂NH₂ is:

A) Benzylamine            B) Phenylmethylamine            C) Both A and B        D) Benzenamine

15.The compound C₆H₅OCH₃ is known as:

A) Methoxybenzene        B) Phenyl methyl ether        C) Anisole                D) All of these

16. The IUPAC name of NO₂C₆H₄COOH (p-isomer) is:

A) 4-Nitrobenzoic acid                B) 2-Nitrobenzoic acid        

C) 3-Nitrobenzoic acid                D) p-Nitrobenzoic acid

 Isomerism 

1. What is the definition of isomerism?

A) Different compounds with the same molecular formula but different arrangements of atoms
B) Compounds with different molecular formulas but similar structures
C) Compounds that have the same physical properties
D) Different elements combined in a compound

2. Which of the following is NOT a type of isomerism?

A) Structural isomerism
B) Geometric isomerism
C) Optical isomerism
D) Ionic isomerism

3. Which type of isomerism arises due to different arrangements of atoms in space around a double bond?

A) Structural isomerism
B) Geometric isomerism
C) Optical isomerism
D) Functional isomerism

4. In optical isomerism, isomers are also called:

A) Enantiomers
B) Diastereomers
C) Conformers
D) Tautomers

5. Which of the following compounds can exhibit geometric isomerism?

A) Ethane (C2H6)
B) Ethene (C2H4)
C) Methane (CH4)
D) Propane (C3H8)

6. Which of the following is an example of functional isomerism?

A) Butane and isobutane
B) Ethanol and dimethyl ether
C) Cis-butene and trans-butene
D) Lactic acid and alanine

7. The phenomenon where compounds have the same formula but differ in the connectivity of atoms is called:

A) Optical isomerism
B) Structural isomerism
C) Geometric isomerism
D) Conformational isomerism

8. Which statement is true about cis-trans isomers?

A) They have different molecular formulas
B) They have the same physical and chemical properties
C) They differ in the spatial arrangement of groups around a double bond or ring
D) They cannot be separated

9. Chirality in molecules is associated with:

A) A plane of symmetry
B) A carbon atom bonded to four different groups
C) A double bond in the molecule
D) Identical groups attached to the carbon atom

10. Which of the following is NOT a property that can differ between isomers?

A) Boiling point
B) Melting point
C) Molecular weight
D) Optical activity

Answer key

1. A) Different compounds with the same molecular formula but different arrangements of atoms
2. D) Ionic isomerism
3. B) Geometric isomerism
4. A) Enantiomers
5. B) Ethene (C2H4)
6. B) Ethanol and dimethyl ether
7. B) Structural isomerism
8. C) They differ in the spatial arrangement of groups around a double
9. B) A carbon atom bonded to four different groups
   
10. C) Molecular weight

Isomerism 2

1. Explain the difference between structural isomerism and stereoisomerism with suitable examples.

2. Draw all possible chain isomers of pentane and name them.

3. What is positional isomerism? Illustrate with an example involving pentene.

4. Define functional isomerism and give two examples of functional isomers with molecular formula C3H6O.

5. Explain tautomerism with the keto-enol tautomerism of acetaldehyde.

6. What is geometrical (cis-trans) isomerism? Draw the cis and trans isomers of 1,2-dichloroethene.

7. Explain why cis-isomers generally have higher boiling points than trans-isomers.

8. Define optical isomerism and explain the role of a chiral center with an example.

9. How many stereoisomers are possible for 2,3-dibromobutane? Explain. 

10. Differentiate between enantiomers and diastereomers with examples.

12. What is racemic mixture? How can it be resolved into individual enantiomers?

14. Discuss the concept of conformational isomerism with reference to ethane.

15.How does the presence of double bonds affect the possibility of rotation and isomerism?

17. Write the number of isomers of C4H8 and classify them.

Answer key 

Chapter GOC

1.     1  
Answer (structural/formula form):
HO–CH₂–CH₂–CH₂–CH(CH₃)–CH(CH₃)–COOH

2. IUPAC name of the compound shown (CH₃–CH(–NO₂)–C(=O)–CH(–CH₃)–CH₃)
   Answer: 2-Nitro-4-methylpentan-3-one

4. The central atom of CH₂=C=CH₂ is ______ hybridized.
   Answer: sp
5. Assertion: Carbocations are planar in nature.
   Reason: Carbocations are sp² hybridized.
   Answer: (a) Both A and R are correct and Reason is the correct explanation.
   (Planarity follows from the empty p orbital and sp² hybridization of the positively charged carbon.)

5. Assertion: All the carbon atoms of But-2-ene lie in a plane.
   Reason: All the carbon atoms in But-2-ene are sp² hybridized.
   Answer: (c) Both Assertion and Reason are incorrect.
   (But-2-ene has two internal sp² carbons that are planar, but the terminal methyl carbons are sp³ — so not all carbons are sp² nor are all carbons in one plane.)

6. (i) What type of isomerism is exhibited by the pair CH₃CH₂CHO and CH₃COCH₃?
   Answer: Functional-group isomerism (aldehyde vs. ketone).

(ii) Give one example each of a nucleophile and an electrophile.
Answer: Nucleophile: OH⁻ (or :NH₃, :CN⁻) — electron pair donor.
Electrophile: H⁺ (or NO₂⁺, R⁺ carbocation) — electron pair acceptor.

Unit Test I — Answers (Questions 1–5)

1. Answer : (d) BF₃ — boron trifluoride is electron-deficient (Lewis acid) and accepts electron pairs, so it acts as an electrophile.

2. Answer: (b) C₆H₅CH·CH₃ — the benzylic secondary radical (adjacent to the aromatic ring) is resonance-stabilized and is more stable than simple alkyl radicals.

3.Hyperconjugation (also called σ-conjugation or Baker–Nathan effect). No-bond resonance refers to delocalization involving σ (C–H or C–C) bonds.

 

4. Assertion: In CH₂ = C = CH₂ all the carbon atoms are sp² hybridized.
Reason : All the hydrogen atoms lie in one plane.

Answer: (c) Both Assertion and Reason are incorrect.
(Explanation: In allene the central carbon is sp hybridized and the terminal carbons are sp²; the terminal CH₂ groups lie in perpendicular planes, so H atoms are not all in one plane.)

5. Assertion: Glycerol is purified by distillation under reduced pressure.
Reason : Organic compound in liquid state are purified by distillation.

Answer: (b) Both Assertion and Reason are correct but Reason is not the correct explanation.
(Explanation: Glycerol is purified by vacuum distillation because it has a high boiling point and would decompose on normal distillation; the Reason is a true general statement but does not explain why reduced pressure is needed.)

6. Give IUPAC name of the following compounds :

(a) C₆H₅CH₂CH₂OH
Answer: 2‑Phenylethanol (common name: phenethyl alcohol).

(b) Structure: CH₃–CH(Br)–C(=O)–CH(CH₃)–CH₃

Answer: 2‑Bromo‑4‑methylpentan‑3‑one
(Parent chain = pentan‑3‑one; substituents at C‑2 = bromo, C‑4 = methyl.)

7. Discuss the principle of steam distillation.

Steam distillation separates volatile, water‑immiscible (or partially immiscible) organic compounds at temperatures below their boiling points. When steam is passed through (or the compound is co‑distilled with water), the total vapour pressure of the system is the sum of vapour pressures of water and the organic compound; the mixture boils when this sum equals atmospheric pressure, allowing distillation at a lower temperature and preventing thermal decomposition.

8. Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.

Fusion with sodium (Lassaigne’s test) converts covalently bound heteroatoms into their corresponding ionic forms (e.g., nitrogen → NaCN/NaCN-derived species, sulphur → Na₂S, halogens → NaX). These inorganic salts are water‑soluble and can be extracted into water and subsequently detected with specific reagents (FeSO₄/HCl for N, lead acetate or sodium nitroprusside for S, silver nitrate for halides).

9. What are the various conditions essential for resonance?

1.      Presence of conjugated π bonds or lone pairs adjacent to π bonds (alternate single and multiple bonds or lone pair–π adjacency).

2.      Planarity of the system so p orbitals can overlap effectively.

3.      Continuous overlap of parallel p orbitals (a cyclic or linear array of p orbitals) to allow delocalization of electrons.

(Any three clear points explaining these ideas earn full credit.)

10. Suggest a method to separate the constituents from the following mixtures :

(a) Mixture of two miscible liquids.
Use fractional distillation (fractionating column). Heat the mixture and collect fractions at different boiling ranges; components separate based on differing boiling points.

(b) A mixture of oil and water.
Use a separatory funnel (liquid–liquid extraction/decantation) to separate the immiscible layers; the denser layer is drained off first. For finer separation, wash with solvents or use centrifugation.

(c) A mixture of plant pigments.
Use chromatography — e.g., column chromatography or paper/TLC to separate pigments based on polarity and adsorption. Often pigments are first extracted with an appropriate solvent (acetone/ethanol) and then separated on a chromatographic medium.

.

 

 

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grade 11 chemistry HH

 

GOC

Nomenclaure test 1

https://forms.gle/aMfPZaWx1Gp5ULoi9

Some Basic Concepts of Chemistry

Chapter 1

ASSERTION AND REASON TYPE QUESTIONS (1 MARK) In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. 

Choose the correct option out of the choices are given below. 

(A) Both A and R are true and R is the correct explanation of A. 

(B) Both A and R are true but R is not the correct explanation of A. 

C) A is true but R is false.

(D) Both A and R are false. 

 

1. Assertion : Equal moles of different substances contain same number of constituent particles. 

Reason : Equal weights of different substances contain the same number of constituent particles.

 

2.Assertion : One atomic mass unit is defined as one-twelfth of the mass of one carbon-12 atom. 

Reason : Carbon-12 isotope is the most abundant isotope of carbon and has been chosen as the standard.

 

3.Assertion (A) : Significant figures for 0.200 is 3 where as for 200 it is 1. 

Reason (R) : Zero at the end or right of a number are significant provided they are not on the right side of the decimal point.

 

4.The number of atoms present in one mole of an element is equal to Avogadro number. Which of the following element contains the greatest number of atoms? 

(a) 4g He                                 (b) 46g Na                              (c) 0.40g Ca                               (d) 12g He

 

5.The significant figures in 0.00051 are ————–. (a) 5 (b) 3 (c) 2 (d) 26

 

6.How many moles of electrons weight one kilogram? 

(a) 6.023 × 10 ²³                     (b) 1/9.1 × 10 ³¹                     (c) 6023×10 ⁵⁴                              (d) 9.1 × 10⁸

 

7.Calculate the number of atoms in each of the following

(i) 52 moles of Ar                               (ii) 52 u of He 

 

8.What is the mass percent of hydrogen in in water? 

(a) 0.034%                             (b) 11.1%                               (c) 3.4%                                     (d) 28.7%

 

9.Which of the following contain highest number of atoms? 

(a) 1.0 g of water                   (b) 1.0 g of silver                    (c) 1.0 g of nitrogen                 (d) 1.0 g of propane

 

10.The number of water molecules is maximum in 

(a) 18 gram of water             (b) 18 moles of water           (c) 18 molecules of water    (d) 1.8 gram of water

 

11.What will be the molarity of a solution which contains 5.85g of NaCl per 500 ml? 

(a) 4 mol/L                             (b) 0.2 mol/L                         (c) 20 mol/L                          (d) 2 mol/L

 

12.Give an example of a molecule in which the ratio of the molecular formula is six times the empirical formula.

 

13.(i) State the law of constant composition (ii) Define molality.

 

14.Calculate the amount of carbon dioxide that could be produced when 

(i) 1 mole of carbon is burnt in air.             (ii) 1 mole of carbon is burnt in 16 g of dioxygen.

 

15.What is stoichiometry? What is the difference between precision and accuracy?

 

16.(a) What do mean by molarity. Calculate the molarity of NaOH in the solution prepared by dissolving its 4 g in enough water to form 250 mL of the solution.

 

17.Determine the empirical & Molecular formulae for a compound with the following elemental composition:40.00% C, 6.66% H, 53.34% O. (Given molecular mass = 180)

 

18.In the reaction: 3C + 4D → 2A + 4B When 5 moles of A react with 6 moles of B then (i) Which is the limiting reagent? (ii) Calculate the amount of C formed?

 

19.Which aqueous solution has higher concentration: 1 molar or 1 molal solution of the same solute? Give reason.

 

20.The molecular mass of an organic compound is 78 and its percentage composition is 92.4 % C and 7.6 % H. Determine the molecular formula of the compound.

 

21.Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation:

 N₂ (g) + H₂ (g) →2NH₃ (g) 

(i) Calculate the mass of ammonia produced if 2.00 x10 3 g dinitrogen reacts with 1.00 x103 g of dihydrogen. 

(ii) Will any of the two reactants remain unreacted?

(iii) If yes, which one and what would be its mass?

 

22.Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction given below: CaCO₃ (s) + 2HCl (aq) → CaCl₂(aq) + CO₂(g) + H₂O

(l) What mass of CaCl₂ will be formed when 250 mL of 0.76 M HCl reacts with 1000 g of CaCO₃ ?

23 Name the limiting reagent. Calculate the number of moles of CaCl₂ formed in the reaction

 

24.The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction 2A + 4B → 3C + 4D, when 5 moles of A react with 6 moles of B, then- 

(i) which is the limiting reagent?                 (ii) calculate the amount of C formed?

 

25. Concentration of solutions: Molarity and Molality are the terms used to express the concentration of the solution. The concentration of a solution is defined as the measure of the quantity of one substance when it is mixed with another substance. The concentration of a chemical solution is measured by both molarity and molality. The major difference between the two is one of mass vs. volume. The molality refers to the number of moles of the solute per unit mass of the solvent, whereas the molarity refers to the number of moles of the solute per unit volume of the solution. If the solution has a solvent and the solute, a Mole Fraction gives a concentration as the ratio of moles of one component to the total moles present in the solution. When the concentration is expressed as the percent of one component in the solution by mass it is called Mass Percentage. 

Answer the following questions: 

a) Give units of molality and molarity. 

b) Which concentration term is a dimensionless quantity? Give its expression. 

c) Calculate the Molarity of 15 % H2SO4 solution by weight having density 1.1 g/mL. 

Atomic masses: H-1, S - 32, O-16 

d)A Solution contains 15gm of sugar in 60gm of water. Find out the mass % for sugar in the solution

 

26.The identity of a substance is defined not only by the types of atoms or ions it contains, but by the quantity of each type of atom or ion. The experimental approach required the introduction of a new unit for amount of substances, the mole, which remains indispensable in modern chemical science. The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter. A mole is defined as the amount of substance containing the same number of discrete entities (atoms, molecules, ions, etc.) as the number of atoms in a sample of pure 12C weighing exactly 12g. One Latin connotation for the word “mole” is “large mass” or “bulk,” which is consistent with its use as the name for this unit. The mole provides a link between an easily measured macroscopic property, bulk mass, and an extremely important fundamental property, number of atoms, molecules and so forth. The number of entities composing a mole has been experimentally determined to be 6.02214179 × 10 ^{23 .}

(i) How many moles of magnesium phosphate, Mg₃(PO₄)₂ will contain 0.25 mole of oxygen atoms? 

(a) 1.25 x 10 ^-2            (b) 2.5 x 10^-2                           (c) 0.02                                    (d) 3.125 x10^-2 

(ii)What is the mass of one molecule of yellow phosphorus? (At. mass of phosphorus =30)

(a)1.993 x 10^-22 mg     (b)1.993 x 10^-19 mg                (c) 4.983 x 10^-20 mg                   (d) 4.983 x 10^-23 mg 

(iii) The number of moles of oxygen in 1L of air containing 21% oxygen by volume, in standard conditions is

 (a) 0.186 mol             (b) 0.21 mol                            (c) 2.10 mol                            (d) 0.0093 mol 

(iv)The number of moles present in 6 gm of carbon is:

(a) 2                            (b) 0.5                                     (c) 5                                         (d) 1 

(v) The mass of an atom of carbon is ————–.

(a) 1g                          (b) 1.99 x 10 _-23 g                   (c) 1/12 g                                 (d) 1.99 x 10 ²³ g

 

"Structure of Atom "

Chapter 2

ASSERTION AND REASON TYPE QUESTIONS (1 MARK) In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. 

Choose the correct option out of the choices are given below. 

(A) Both A and R are true and R is the correct explanation of A. 

(B) Both A and R are true but R is not the correct explanation of A. 

(C) A is true but R is false.

(D) Both A and R are false. 

 

1.     Assertion: In Lyman series of H-spectra, the maximum wavelength of lines is 121.56nm.

Reason: Wavelength is maximum when the transition is from the very next level.

 

2.Assertion: According to Thomson model of atom, mass of the atom is concentrated in the centre of the atom. 

Reason: According the Thomson model, positive charge is concentrated in the centre of the atom.

 

3.Assertion (A): It is impossible to determine the exact position and exact momentum of an electron simultaneously.

Reason (R): The path of an electron in an atom is clearly defined.

 

4.Assertion (A) : Black body is an ideal body that emits and absorbs radiations of all frequencies.

Reason (R) : The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature

 

5.Principal, Azimuthal, and magnetic quantum numbers are respectively related to: 

(a) size , shape, and orientation                               (b)shape, size and orientation 

(c) size, orientation and shape                                 (d) none of above 

 

6.Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons? 

(a) Pauli’s exclusion principle.                                 (b) Heisenberg’s uncertainty principle. 

(c) Hund’s rule of maximum multiplicity.             (d) Aufbau principle

 

7.Which of the following will not show deflection from the path on passing through an electric field? 

(a) Proton                   (b) cathode rays                                 (c) electron                                  (d) neutron

 

8.The magnetic quantum number specifies 

(a) Size of orbitals                                                                 (b) Shape of orbitals                  

(c) Orientation of orbitals                                                    (d) Nuclear Stability

 

9.Consider the isoelectronic series: K+ , S2- , Cland Ca2+, radii of the ions decrease as 

(a) Ca²⁺ < K⁺ > Cl^– , S^2-                                                         (b) Cl^– > S^2- > K⁺ > Ca²⁺ 

(c) S^2- > Cl^– > K⁺ > Ca²⁺                                                        (d) K⁺ > Ca²⁺ > S^2- > Cl^-

 

10.Rutherford’s Alpha particle scattering experiment eventually led to the conclusion that 

(a) mass and energy are related                   (b) electrons occupy space around the nucleus 

(c) neutrons are buried deep in the nucleus (d) the point of impact with matter can be precisely determined

 

11.Which of the following statement is not correct about the characteristics of cathode rays? 

(a) They start from the cathode and move towards the anode. 

(b) They travel in straight line in the absence of an external electrical or magnetic field. 

(c) Characteristics of cathode rays do not depend upon the material of electrodes in cathode ray tube. 

(d) Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube.

 

12.State the following

(i) Aufbau’s principle                        (ii) Heisenberg uncertainty principle 

 

13.Calculate the wave number of line associated with the transition in Balmer series when the electron moves to n = 4 orbit. (R_H = 109677 cm^–1 )

 

14.What is Heisenberg’s uncertainty Principle? What is it’s significance?

15.Write the electronic configuration of the Ni²⁺ (Z=28) and Cr (Z=24) .

 

16.Attempt any 3 of the following

a) State Pauli’s Exclusion Principle. 

b) Write the electronic configuration of Cu²⁺ ion. 

c) Calculate the total number of angular nodes and radial nodes present in the 3p orbital. 

d) How many numbers of electrons having- n = 3 , m _s = -½

 

17.The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on its outer shell electrons is: (i) s > p > d > f (ii) f > d > p > s (iii) p < d < s > f (iv) f > p > s > d

 

18.The three dimensional space where probability of finding the electrons is maximum is called

(a) Orbit                     (b) Orbital                  (c) Octet                     (d) Nodes 

 

19.Which of the following is iso-electronic with neon - 

(A) O^2–                       (B) F⁺                          (C) Mg                                    (D) Na

 

20.The value of l and m for the last electron in the Cl^– ion are - 

(A) 1 and 2                 (B) 2 and +1              (C) 3 and –1               (D) 1 and –1

 

21.Which of the following set of quantum numbers is not possible? 

(a) n = 3, l = 0, m = 0             `                         (b) n = 3, l = 1, m = -1                       

 (c) n = 2, l = 0, m = -1                       (d) n = 2, l = 1, m = 0 

 

22.The ground state electronic configuration of Fe3+ ion is 

(a) [Ar] 3d³ 4s²           (b) [Ar] 3d⁶ 4s²           (c) [Ar] 3d⁵     (d) [Ar] 3d⁶

 

23.Which of the following rule out the existence of definite path or trajectories of electrons

(A) Pauli’s exclusion principle                                             (B) Heisenberg’s uncertainty principle 

(C) Hund’s rule of maximum multiplicity                         (D) Aufbau’s principle

What were the reasons for it’s failure of Bohr’ model?

 

24.Find the de Broglie wavelength for an electron moving at the speed of 2.19×10 ⁶ ms−1

(Given: Mass of an electron = 9.1×10^-31 kg & h = 6.6 x 10 ^-34 Js) 

 

25.(i) State two postulates of Bohr’s model of hydrogen atom. 

(ii) Write a drawback of Bohr’s model of hydrogen atom. 

 

26.a) i) How many sub-shells are associated with n = 4 ?

ii) How many electrons will be present in the sub-shells having ms value of -1/2 for n = 4 ? 

b) An ion with mass number 37 possesses one unit of negative charge. If the ion contains 11 .1% more neutrons than the electrons, find the symbol of the ion.

 

27.(i) Calculate wave number of yellow radiations having wavelength of 5800 A0 . 

(ii) What are the values of n and l for 4f orbital 

 

28.Calculate the wavelength and frequency of light wave whose period is 2.0 × 10^-10 s.

 

29.(i) The electron energy in hydrogen atom is given by En = (–2.18 x10^-18)/n 2 J. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition. 

(ii) Find the energy of the 3th Bohr’s orbit of He⁺ ion. 

(iii) Calculate the number of radial nodes for 2p orbital

 

 30.(i) How many electrons in an atom may have the following quantum numbers? 

(a) n = 4, ms = – ½ (b) n = 3, l = 0 

(ii) Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit. 

(iii) What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to the ground state?

 

31.Read the given passage and answer the questions. Orbitals are regions or spaces where there is a maximum probability of finding electrons. Qualitatively, these orbitals can be distinguished by their size, shape, and orientation. An orbital of small size means there is more chance of finding the electron near the nucleus. Shape and orientation mean the direction in which the probability of finding the electron is maximum. Atomic orbitals can be distinguished by quantum numbers. Each orbital is designated by three quantum numbers n, l, and ml (magnetic quantum number) which define energy, shape, and orientation but these are not sufficient to explain spectra of multi-electrons atoms. Spin quantumn number (ms ) determines the spin of electrons. Spin angular momentum of the electron has two orientations relative to the chosen axis which are distinguished by spin quantum numbers ms which can take values +1/2 and –1/2 

I. How many orbitals are associated with n = 3? 

II. How many electrons are possible in an orbital? Why? 

III. What is the shape of ‘s’ and ‘p’ orbitals? 

IV. Name two d-orbitals that are on-axis.