# Chemistry Delhi Set 3 2016-2017 CBSE (Arts) Class 12 Question Paper Solution

Chemistry [Delhi Set 3]
Date & Time: 24th March 2017, 12:30 pm
Duration: 3h

[1]1

What is the effect of catalyst on: Gibbs energy (∆G)

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

What is the effect of catalyst on activation energy of a reaction?

Concept: Relation Between Gibbs Energy Change and Emf of a Cell
Chapter: [3] Electrochemistry
[1]2

Write one similarity between Physisorption and Chemisorption

Chapter: [5] Surface Chemistry
[1]3

Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.

Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Chapter: [8] "D" and "F" Block Elements
[1]4

Write the structure of 3-Bromo-2-methylprop-1-ene

Concept: Preparation of Ethers from Dehydration of Alcohols and Williamson Systhesis
Chapter: [11] Alcohols, Phenols and Ethers
[1]5

Write IUPAC name of the following compound (CH3)2 N − CH2CH3

Concept: Alcohols, Phenols and Ethers - Nomenclature
Chapter: [11] Alcohols, Phenols and Ethers
[2]6

Write the reactions involved in the following reactions: Clemmensen reduction

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

Write the reactions involved in the following reactions: Cannizzaro reaction

Concept: Aldehydes and Ketones - Nomenclature
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[2]7

Draw the structures of the following: H4P2O7 (Pyrophosphoric acid)

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

Write the structures of the following molecules: XeOF4

Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
Chapter: [7] P - Block Elements
[2]8

Define the term Abnormal molar mass

Concept: Abnormal Molar Masses
Chapter: [2] Solutions

Define van’t Hoff factor.

Concept: Abnormal Molar Masses
Chapter: [2] Solutions
[2]9

Calculate the degree of dissociation (α) of acetic acid if its molar conductivity (Λm) is 39.05 S cm2 mol−1.

Given λ°(H+) = 349.6 S cm2 mol−1 and λ°(CH3COO) = 40.9 S cm2 mol−1

Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
Chapter: [3] Electrochemistry
[2]10 | Attempt Any One
[2]10.1

Complete the given chemical equations

F_2 + 2Cl^(-)

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

Complete the given chemical equations:

2XeF_2 + 2H_2O->

Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
Chapter: [7] P - Block Elements
[2]10.2

What happens when HCl is added to MnO2? Write the equations involved

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

What happens when PCl5 is heated? Write the equations involved.

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
[3]11

Give reasons  Acetylation of aniline reduces its activation effect.

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

Give reasons CH3NH2 is more basic than C6H5NH2.

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

Give reasons  Although –NH2 is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline

Concept: Amines - Nomenclature
Chapter: [13] Organic Compounds Containing Nitrogen
[3]12

Give reasons Thermal stability decreases from H2O to H2Te.

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

Give reasons Fluoride ion has higher hydration enthalpy than chloride ion.

Concept: Alcohols, Phenols and Ethers - Nomenclature
Chapter: [11] Alcohols, Phenols and Ethers

Account for the following : Nitrogen does not form pentahalide.

Concept: P - Block Group 15 Elements - Dinitrogen
Chapter: [7] P - Block Elements
[3]13

Explain the following terms with suitable examples - Anionic detergents

Concept: Cleansing Agents - Synthetic Detergents
Chapter: [16] Chemistry in Everyday Life

Define Broad-spectrum antibiotics with a suitable example?

Concept: Drugs and Their Classification
Chapter: [16] Chemistry in Everyday Life

Explain Tranquilizers

Concept: Drugs and Their Classification
Chapter: [16] Chemistry in Everyday Life
[3]14

Write the names and structures of the monomers of the following polymers: Nylon-6

Concept: Introduction of Polymers
Chapter: [15] Polymers

Write the structures of the monomers used for getting the following polymers

Melamine – formaldehyde polymer

Concept: Polymers - Some Important Polymers
Chapter: [15] Polymers

Write the names of monomers used for getting the following polymers:

Teflon

Concept: Polymers - Classification of Polymers Based on Structure
Chapter: [15] Polymers
[3]15 | Attempt Any One
[3]15.1

Write structures of compounds A, B and C in of the following reactions

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds

Write structures of compounds A, B and C in of the following reactions

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
[3]15.2

How will you bring about the following conversions in not more than two steps?

Benzoic acid to Benzaldehyde

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

Do the following conversions in not more than two steps :

Ethyl benzene to Benzoic acid

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

Do the following conversions in not more than two steps :

Propanone to Propene

Concept: Amines - Nomenclature
Chapter: [13] Organic Compounds Containing Nitrogen
[3]16

Name the method of refining of metals such as Germanium.

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

Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation process preferably?

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

What is the significance of leaching in the extraction of aluminium?

Concept: Types of Separation Or Concentration of an Ore - Leaching
Chapter: [6] General Principles and Processes of Isolation of Elements
[3]17

Following compounds are given to you :

2-Bromopentane, 2-Bromo-2-methylbutane, 1-Bromopentane

1) Write the compound which is most reactive towards SN2 reaction.

2) Write the compound which is optically active.

3)  Write the compound which is most reactive towards β-elimination reaction.

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
[3]18

Following data are obtained for reaction :

N2O5 → 2NO2 + 1/2O2

 t/s 0 300 600 [N2O5]/mol L–1 1.6 × 10-2 0.8 × 10–2 0.4 × 10–2

1) Show that it follows first order reaction.

2) Calculate the half-life.

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

Concept: Integrated Rate Equations - First Order Reactions
Chapter: [4] Chemical Kinetics
[3]19

Write one difference between Multimolecular colloid and Macromolecular colloid

Concept: Classification of Colloids - Classification Based on Physical State of Dispersed Phase and Dispersion Medium
Chapter: [5] Surface Chemistry

Write one difference between Sol and Gel

Concept: Classification of Colloids - Classification Based on Physical State of Dispersed Phase and Dispersion Medium
Chapter: [5] Surface Chemistry

Write one difference between O/W emulsion and W/O emulsion

Concept: Classification of Colloids - Classification Based on Physical State of Dispersed Phase and Dispersion Medium
Chapter: [5] Surface Chemistry
[3]20

What type of isomerism is shown by the complex [Co(en)3]Cl3

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

Write the hybridisation and magnetic character of [Co(C2O4)3]3–.

(At. no. of Co = 27)

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

Write IUPAC name of the following Complex [Cr(NH3)3Cl3]

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
[3]21

Calculate the mass of Ag deposited at cathode when a current of 2 amperes was passed through a solution of AgNO3 for 15 minutes.

(Given : Molar mass of Ag = 108 g mol−1 lF = 96500 C mol−1)

Concept: Electrolytic Cells and Electrolysis - Introduction
Chapter: [3] Electrochemistry

Define terms: Fuel cell

Concept: Batteries - Primary Batteries
Chapter: [3] Electrochemistry
[3]22

A 10% solution (by mass) of sucrose in water has 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−1)

(Molar mass of glucose = 180 g mol−1)

Concept: Carbohydrates - Preparation of Glucose from Sucrose (Cane Sugar) and Starch
Chapter: [14] Biomolecules
[4]23

After watching a programme on TV about the presence of carcinogens (cancer causing agents) Potassium bromate and Potassium iodate in bread and other bakery products, Ritu a class XII student decided to aware others about the adverse effects of these carcinogens in foods. She consultanted the school principal and requested him to instruct canteen contractor to stop selling sandwiches, pizza, burgers and other bakery products to the students. Principal took an immediate action and instructed the canteen contractor to replace the bakery products with some proteins and vitamins rich food like fruits, salads, sprouts etc. The decision was welcomed by the parents and students.

1) What are the values (at least two) displayed by Ritu?

2) Which polysaccharide component of carbohydrates is commonly present in bread?

3) Write the two types of secondary structure of proteins.

4) Give two examples of water soluble vitamins.

Concept: Introduction of Proteins
Chapter: [14] Biomolecules
[5]24 | Attempt Any One
[5]24.1

An element has atomic mass 93 g mol–1 and density 11.5 g cm–3. If the edge length of its unit cell is 300 pm, identify the type of unit cell

Concept: Number of Atoms in a Unit Cell
Chapter: [1] Solid State

Write any two differences between amorphous solids and crystalline solids

Concept: Amorphous and Crystalline Solids
Chapter: [1] Solid State
[5]24.2

Calculate the number of unit cells in 8.1 g of aluminium if it crystallizes in a f.c.c. structure. (Atomic mass of Al = 27 g mol–1)

Concept: Number of Atoms in a Unit Cell
Chapter: [1] Solid State

Give reasons : In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel defect.

Concept: Imperfections in Solids - Types of Point Defects - Stoichiometric Defects
Chapter: [1] Solid State

Give reasons : Silicon on doping with Phosphorous forms n-type semiconductor.

Concept: Electrical Properties - Applications of N-type and P-type Semiconductors
Chapter: [1] Solid State

Give reasons:Ferrimagnetic substances show better magnetism than antiferromagnetic substances.

Concept: Magnetic Properties
Chapter: [1] Solid State
[5]25 | Attempt Any One
[5]25.1

Write the product(s) in the following reactions

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

Write the product(s) in the following reactions

Concept: Physical Properties of Ethers
Chapter: [11] Alcohols, Phenols and Ethers

Write the product(s) in the following reaction

Concept: Chemical Reaction of Ethers - Cleavege of C-O Bonds
Chapter: [11] Alcohols, Phenols and Ethers

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

Ethanol and phenol

Concept: Physical and Chemical Properties of Alcohols and Phenols
Chapter: [11] Alcohols, Phenols and Ethers

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

Propanol and 2-methylpropan-2-ol

Concept: Physical Properties of Ethers
Chapter: [11] Alcohols, Phenols and Ethers
[5]25.2

Write the formula of reagents used in the following reactions :

Bromination of phenol to 2,4,6-tribromophenol

Concept: Chemical Reaction of Ethers - Cleavege of C-O Bonds
Chapter: [11] Alcohols, Phenols and Ethers

Write the formula of reagents used in the following reactions :

Hydroboration of propene and then oxidation to propanol.

Concept: Chemical Reaction of Ethers - Cleavege of C-O Bonds
Chapter: [11] Alcohols, Phenols and Ethers

Arrange the following compound groups in the increasing order of their property indicated :

p-nitrophenol, ethanol, phenol (acidic character)

Concept: Introduction of Coordination Compounds
Chapter: [9] Coordination Compounds

Arrange the following compound groups in the increasing order of their property indicated :

Propanol, Propane, Propanal (boiling point)

Concept: Introduction of Coordination Compounds
Chapter: [9] Coordination Compounds

Write the mechanism (using curved arrow notation) of the following reaction :

Concept: Chemical Reactions of Alcohols and Phenols - Reactions Involving Cleavage of Carbon–Oxygen (C–O) Bond in Alcohols
Chapter: [11] Alcohols, Phenols and Ethers
[5]26 | Attempt Any One
[5]26.1

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

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

Give examples and suggest reasons for the following features of the transition metal chemistry:

The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.

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

Account for the following:

E° value for the Mn3+/Mn2+ couple is highly positive (+1.57 V) as compare to Cr3+/Cr2+.

Concept: Galvanic Cells - Measurement of Electrode Potential
Chapter: [3] Electrochemistry

Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

Concept: F-block Elements - The Actinoids
Chapter: [8] "D" and "F" Block Elements
[5]26.2

How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

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

Explain why Cu+ ion is not stable in aqueous solutions?

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

Orange colour of Cr_2O_7^(2–) ion changes to yellow when treated with an alkali. Why?

Concept: Amines - Chemical Reactions of Amines - Alkylation and Acylation
Chapter: [13] Organic Compounds Containing Nitrogen

How would you account for the following:

The chemistry of actinoids is more complicated as compared to lanthanoids.

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

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