CBSE (Commerce) Class 12CBSE
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Question Paper Solutions - Chemistry 2013 - 2014 CBSE (Commerce) Class 12

Alternate Sets

   

Marks: 70
[1]1

What is the effect of temperature on chemisorption ?

Chapter: [5] Surface Chemistry
Concept: Adsorption - Types of Adsorption
[1]2

What is the role of zinc metal in the extraction of silver ?

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Oxidation Reduction
[1]3

What is the basicity of H3PO3 ?

Chapter: [7] P - Block Elements
Concept: P - Block Group 15 Elements - Oxoacids of Phosphorus
[1]4

Identify the chiral molecule in the following pair :

 

Chapter: [10] Haloalkanes and Haloarenes
Concept: Haloalkanes - R-s and D-l Configuration
[1]5

Which of the following is a natural polymer ? Buna-S, Proteins, PVC

Chapter: [15] Polymers
Concept: Types of Polymerisation Reactions - Addition Polymerisation Or Chain Growth Polymerisation
[1]6

The conversion of primary aromatic amines into diazonium salts is known as ___________

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Introduction of Diazonium Salts
[1]7

What are the products of hydrolysis of sucrose ?

Chapter: [14] Biomolecules
Concept: Carbohydrates - Oligosaccharides
[1]8

Write the structure of p-methylbenzaldehyde.

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Structure of the Carbonyl Group
[2]9

An element with density 2.8 g cm–3 forms a f.c.c. unit cell with edge length 4 x 10–8 cm. Calculate the molar mass of the element.

(Given : NA = 6.022 x 1023 mol –1)

Chapter: [1] Solid State
Concept: Calculations Involving Unit Cell Dimensions
[2]10
[2]10.1

What type of non-stoichiometric point defect is responsible for the pink colour of LiCl ?

Chapter: [1] Solid State
Concept: Imperfections in Solids - Introduction

What type of stoichiometric defect is shown by NaCl ?

Chapter: [1] Solid State
Concept: Imperfections in Solids - Introduction
[2]10.2

How will you distinguish between the following pairs of terms: Tetrahedral and octahedral voids

Chapter: [1] Solid State
Concept: Close Packed Structures - Formula of a Compound and Number of Voids Filled

How will you distinguish between the following pairs of terms : Crystal lattice and unit cell

 

Chapter: [1] Solid State
Concept: Crystal Lattices and Unit Cells - Introduction
[2]11

State Kohlrausch law of independent migration of ions. 

Chapter: [3] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration

Why does the conductivity of a solution decrease with dilution ?

Chapter: [3] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
[2]12

For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as:

(i) Predict the order of the reaction.

(ii) What is the slope of the curve ?

Chapter: [4] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[2]13

Explain the principle of the method of electrolytic refining of metals. Give one example.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Refining
[2]14

Complete the following equations : P4 + H2O →

Chapter: [7] P - Block Elements
Concept: P - Block Group 15 Elements - Oxoacids of Phosphorus

Complete the following equations : XeF4 + O2F2

Chapter: [7] P - Block Elements
Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
[2]15

Draw the structures of the following molecules: XeF2

 

Chapter: [7] P - Block Elements
Concept: P - Block Group 18 Elements - Concept of Group 18 Elements

Draw the structures of the following molecules: BrF3

Chapter: [7] P - Block Elements
Concept: P - Block Group 17 Elements - Interhalogen Compounds
[2]16

Write the equations involved in the following reactions : Reimer – Tiemann reaction

Chapter: [11] Alcohols, Phenols and Ethers
Concept: Chemical Reactions of Phenols (Only)

Write the equations involved in the following reactions : Williamson synthesis

Chapter: [11] Alcohols, Phenols and Ethers
Concept: Preparation of Ethers from Dehydration of Alcohols and Williamson Systhesis
[2]17

Write the mechanism of the following reaction :

Chapter: [11] Alcohols, Phenols and Ethers
Concept: Chemical Reactions of Alcohols and Phenols - Reactions Involving Cleavage of Carbon–Oxygen (C–O) Bond in Alcohols
[2]18

Write the name of monomers used for getting the following polymers : Bakelite

Chapter: [15] Polymers
Concept: Polymers - Classification of Polymers Based on Structure

Write the name of monomers used for getting the following polymers : Neoprene

Chapter: [15] Polymers
Concept: Polymers - Classification of Polymers Based on Molecular Forces
[3]19

Calculate ΔrG° for the reaction 

Mg (s) + Cu2+ (aq) → Mg2+ (aq) + Cu (s)

Given : E°cell = + 2.71 V, 1 F = 96500 C mol–1

Chapter: [3] Electrochemistry
Concept: Relation Between Gibbs Energy Change and Emf of a Cell

Name the type of cell which was used in Apollo space programme for providing electrical power.

Chapter: [3] Electrochemistry
Concept: Batteries - Primary Batteries
[3]20

The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume :

SO2Cl2 (g) → SO2 (g) + Cl2 (g)

Experiment Time/s–1 Total pressure/atm
1 0 0.4
2 100 0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

Chapter: [4] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[3]21

What are emulsions?

Chapter: [5] Surface Chemistry
Concept: Emulsions

What are their different types emulsions? Give one example of each type.

Chapter: [5] Surface Chemistry
Concept: Emulsions
[3]22

Give reasons for the following : (CH3)3 P = O exists but (CH3)3 N = O does not.

Chapter: [7] P - Block Elements
Concept: Concept of Group 15 Elements

Give reasons for the following : Oxygen has less electron gain enthalpy with negative sign than sulphur.

Chapter: [7] P - Block Elements
Concept: Concept of Group 16 Elements

Give reasons for the following : H3PO2 is a stronger reducing agent than H3PO3.

 

Chapter: [7] P - Block Elements
Concept: P - Block Group 15 Elements - Oxoacids of Phosphorus
[3]23

Write the IUPAC name of the complex [Cr(NH3)4 Cl2]Cl.

Chapter: [9] Coordination Compounds
Concept: Nomenclature of Coordination Compounds - Naming of Mononuclear Coordination Compounds

What type of isomerism is exhibited by the complex [Co(en)3]3+?

(en = ethane-1,2-diamine)

Chapter: [9] Coordination Compounds
Concept: Isomerism in Coordination Compounds - Stereoisomerism

[NiCl4]2− is paramagnetic, while [Ni(CO)4] is diamagnetic, though both are tetrahedral. Why? (Atomic number of Ni = 28)

Chapter: [9] Coordination Compounds
Concept: Bonding in Coordination Compounds - Magnetic Properties of Coordination Compounds
[3]24

Draw the structures of major monohalo products in each of the following reactions :

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of C-OH Bond

Draw the structures of major monohalo products in each of the following reactions :

Chapter: [10] Haloalkanes and Haloarenes
Concept: Methods of Preparation of Haloalkanes and Haloarenes

Which halogen compound in each of the following pairs will react faster in SN2 reaction CH3Br or CH3I

Chapter: [7] P - Block Elements
Concept: P - Block Group 17 Elements - Concept of Group 17 Elements

Which halogen compound in each of the following pairs will react faster in SN2 reaction

(CH3)3 C – Cl or CH3 – Cl

Chapter: [7] P - Block Elements
Concept: P - Block Group 17 Elements - Concept of Group 17 Elements
[3]25 | Attempt Any One
[3]25.1

Give reasons for the following: Primary amines have higher boiling point than tertiary amines.

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Physical Properties of Amines

Give reasons for the following:

Aniline does not undergo Friedal- Crafts reaction.

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Amines - Chemical Reactions of Amines - Electrophilic Substitution

Give reasons for the following: (CH3)2NH is more basic than (CH3)3N in an aqueous solution.

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Physical Properties of Amines
[3]25.2

Give the structures of A, B and C in the following reactions :

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Amines - Preparation of Amines

Give the structures of A, B and C in the following reactions :

Chapter: [13] Organic Compounds Containing Nitrogen
Concept: Amines - Preparation of Amines
[3]26

Define the following terms as related to proteins :

Peptide linkage

Chapter: [14] Biomolecules
Concept: Proteins - Peptide

Define the following terms as related to proteins :

Primary structure

Chapter: [14] Biomolecules
Concept: Proteins - Classification of Amino Acids

Define the following terms as related to proteins:

Denaturation

Chapter: [14] Biomolecules
Concept: Proteins - Denaturation of Proteins
[3]27

On the occasion of World Health Day, Dr. Satpal organized a ‘health camp’ for the poor farmers living in a nearby village. After check-up, he was shocked to see that most of the farmers suffered from cancer due to regular exposure to pesticides and many were diabetic. They distributed free medicines to them. Dr. Satpal immediately reported the matter to the
National Human Rights Commission (NHRC). On the suggestions of NHRC, the government decided to provide medical care, financial assistance, setting up of super-speciality hospitals for treatment and prevention of the deadly disease in the affected villages all over India.

(i) Write the values shown by

(a) Dr. Satpal

(b) NHRC

(ii) What type of analgesics are chiefly used for the relief of pains of terminal cancer ?

(iii) Give an example of artificial sweetener that could have been recommended to diabetic patients

Chapter: [16] Chemistry in Everyday Life
Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
[5]28 | Attempt Any One
[5]28.1

Define the following terms : Molarity

Chapter: [2] Solutions
Concept: Solubility - Solubility of a Solid in a Liquid

Define the following terms : Molal elevation constant (Kb)

Chapter: [2] Solutions
Concept: Colligative Properties and Determination of Molar Mass - Elevation of Boiling Point

A solution containing 15 g urea (molar mass = 60 g mol–1) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 g mol–1) in water. Calculate the mass of glucose present in one litre of its solution.

Chapter: [2] Solutions
Concept: Colligative Properties and Determination of Molar Mass - Osmosis and Osmotic Pressure
[5]28.2

What type of deviation is shown by a mixture of ethanol and acetone ? Give reason.

Chapter: [2] Solutions
Concept: Vapour Pressure of Liquid Solutions - Vapour Pressure of Liquid- Liquid Solutions

A solution of glucose (molar mass = 180 g mol–1) in water is labelled as 10% (by mass). What would be the molality and molarity of the solution ? (Density of solution = 1.2 g mL–1)

Chapter: [2] Solutions
Concept: Colligative Properties and Determination of Molar Mass - Introduction
[5]29
[5]29.1

Complete the following equations:Cr2O72- + 2OH

Chapter: [8] "D" and "F" Block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Complete the following equations : MnO4- + 4H+ + 3e- →

Chapter: [8] "D" and "F" Block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Account for the following :

Zn is not considered as a transition element.

Chapter: [8] "D" and "F" Block Elements
Concept: General Properties of the Transition Elements (D-block)

How would you account for the following: Transition metals form complex compounds.

Chapter: [8] "D" and "F" Block Elements
Concept: General Properties of the Transition Elements (D-block)

Account for the following : The E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+ couple.

Chapter: [8] "D" and "F" Block Elements
Concept: General Properties of the Transition Elements (D-block)
[5]29.2

With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids

Chapter: [8] "D" and "F" Block Elements
Concept: F-block Elements - The Actinoids

Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.

Chapter: [8] "D" and "F" Block Elements
Concept: F-block Elements - The Lanthanoids

Complete the following equation : MnO4- + 8H+ + 5e- →

Chapter: [8] "D" and "F" Block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Out of Mn3+ and Cr3+, which is more paramagnetic and why ?

(Atomic nos. : Mn = 25, Cr = 24)

Chapter: [8] "D" and "F" Block Elements
Concept: General Properties of the Transition Elements (D-block)
[5]30 | Attempt Any One
[5]30.1

Write the products formed when CH3CHO reacts with the following reagents : HCN

 

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Nucleophilic Addition Reactions

Write the products formed when CH3CHO reacts with the following reagents : H2N – OH

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Nucleophilic Addition Reactions

Write the products formed when CH3CHO reacts with the following reagents: CH3CHO in the presence of dilute NaOH

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Reactions Due to A-hydrogen

Give simple chemical tests to distinguish between the following pairs of compounds:  Benzoic acid and Phenol

Chapter: [11] Alcohols, Phenols and Ethers
Concept: Chemical Reactions of Phenols (Only)

Give simple chemical tests to distinguish between the following pairs of compounds

Propanal and Propanone

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Oxidation
[5]30.2

Account for the following : Cl – CH2COOH is a stronger acid than CH3COOH.

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Substitution Reactions in the Hydrocarbon Part

Why carboxylic acid does not give reactions of carbonyl group?

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Carboxylic Acids - Structure of the Carboxyl group

Write the chemical equations to illustrate the following name reactions : Rosenmund reduction

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Preparation of Aldehydes

Write the chemical equations to illustrate the following name reactions : Cannizzaro’s reaction

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Other Reactions

Out of CH3CH2 – CO – CH2 – CH3 and CH3CH2 – CH2 – CO – CH3, which gives iodoform test?

Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Oxidation
S