HSC Science (Computer Science) 12th Board ExamMaharashtra State Board
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Question Paper Solutions - Chemistry 2016 - 2017 HSC Science (Computer Science) 12th Board Exam


Marks: 70
[7]1 | Select and write the most appropriate answer from the given alternatives for each sub-question:
[1]1.1

Which of the following is a basic oxide?

(A) SiO2

(B) P4O10

(C) MgO

(D) Al2O3

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Oxides of Nitrogen
[1]1.2

In the representation of galvanic cell, the ions in the same phase are separated by a _______.

(A) single vertical line

(B) comma

(C) double vertical line

(D) semicolon

Chapter: [4] Electrochemistry
Concept: Galvanic Cells - Introduction
[1]1.3

An ionic crystal lattice has limiting value of radius ratio as 0.414 to 0.732; the co-ordination number of its cation is _______.

(A) 6

(B) 4

(C) 3

(D) 12

Chapter: [1] Solid State
Concept: Crystal Lattices and Unit Cells - Introduction
[1]1.4

The unit of rate constant for zero order reaction is _______.

(A) t–1

(B) mol dm–3 t–1

(C) mol–1 dm3 t–1

(D) mol–2 dm6 t–1

Chapter: [5] Chemical Kinetics
Concept: Integrated Rate Equations - Half-life of a Reaction
[1]1.5

Calcium carbonate used in the extraction of iron acts as _______.

(A) oxidising agent

(B) reducing agent

(C) gangue

(D) flux

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: General Principles and Processes of Isolation of Elements - Principles and Methods of Extraction - Concentration
[1]1.6

10.0 grams of caustic soda when dissolved in 250 cm3 of water, the resultant gram molarity of solution is _______.

(A) 0.25 M

(B) 0.5 M

(C) 1.0 M

(D) 0.1 M

Chapter: [4] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
[1]1.7

55 L atm of work is obtained when 1.0 mole of an ideal gas is compressed isothermally from
a volume of 28.5 L to 18.5 L, the constant external pressure is

(A) 5.05 atm

(B) 5.5 atm

(C) 0.05 atm

(D) 0.55 atm

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Work, Heat, Energy, Extensive and Intensive Properties
[12]2 | Answer any SIX of the following:
[2]2.1

State Henry’s law.

Chapter: [2] Solutions and Colligative Properties
Concept: Solubility - Solubility of a Gas in a Liquid

What is the effect of temperature on solubility of a gas in a liquid?

Chapter: [2] Solutions and Colligative Properties
Concept: Solubility - Solubility of a Gas in a Liquid
[2]2.2

How is nitric acid prepared by Ostwald’s process?

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Nitric Acid
[2]2.3

Classify the following solids into different types:

a. Ammonium phosphate

b. Brass

c. S8 molecule

d. Diamond

Chapter: [1] Solid State
Concept: Classification of Crystalline Solids
[2]2.4

Construct a labelled diagram for the following cell:

`Zn|Zn^(2+)(1M)||H^+(1M)|H_(2(g,1atm))|Pt`

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: General Principles and Processes of Isolation of Elements - Principles and Methods of Extraction - Concentration
[2]2.5

Explain the nature of zinc oxide with the help of the reactions.

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Simple Oxides
[2]2.6

Write the names and chemical formulae of any ‘two’ minerals of aluminium.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[2]2.7

The rate law for the reaction

`2H_(2(g))+2NO_((g))->N_(2(g))+2H_2O_((g))`

is given by rate= `K[H_2][NO]^2`

The reaction occurs in the following two steps:

a. `H_(2(g)) +2NO_((g))->N_2O_((g))+H_2O_((g))`

b. `N_2O_((g))+H_(2(g))->N_(2(g))+H_2O_((g))`

What is the role of N2O in the mechanism? What is the molecularity of each of the elementary steps?

Chapter: [5] Chemical Kinetics
Concept: Rate of a Chemical Reaction
[2]2.8

Write mathematical equation of first law of thermodynamics for Adiabatic process

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics

Write mathematical equation of first law of thermodynamics for Isochoric process

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics

Write the mathematical expression of the First Law of Thermodynamics for  Isothermal Process

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics

Write the mathematical expression of the First Law of Thermodynamics for the Isobaric process

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics
[9]3 | Answer any THREE of the following:
[3]3.1

From the following data for the liquid phase reaction A → B, determine the order of reaction
and calculate its rate constant 

t/s 0 600 1200 1800
[A]/`molL^-1` 0.624 0.446 0.318 0.226
Chapter: [5] Chemical Kinetics
Concept: Rate of a Chemical Reaction
[3]3.2

Calculate the standard enthalpy of combustion of CH3COOH(l) from the following data:

`Delta_fH^@(CO_2)=-393.3 kJ mol^-1`

`Delta_fH^@(H_2O)=-285.8 kJ mol^-1`

`Delta_fH^@(CH_3COOH)=-483.2 kJ mol^-1`

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Enthalpy of Bond Dissociation
[3]3.3

Write the cell representation and calculate equilibrium constant for the following redox reaction:

`Ni_((s))+2Ag_((aq))^+ (1M)->Ni_((aq))^(2+)(1M)+2Ag_((s)) " at "25^@ C`

`E_(ni)^+`=-0.25V and `E_(Ag)^+=0.799V`

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Oxidation Reduction
[3]3.4

What is the action of concentrated sulphuric acid on phosphorous pentachloride

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Sulphuric Acid

What is the action of concentrated sulphuric acid on copper

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Sulphuric Acid

What is the action of concentrated sulphuric acid on potassium chlorate?

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Sulphuric Acid
[7]4 | Answer any ONE of the following:
[7]4.1

Define Molality

Chapter: [2] Solutions and Colligative Properties
Concept: Expressing Concentration of Solutions

Define Osmotic pressure

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

Write any ‘two’ advantages of calomel electrode. 

Chapter: [4] Electrochemistry
Concept: Relation Between Gibbs Energy Change and Emf of a Cell

A metal crystallises into two cubic faces namely face centered (FCC) and body centered (BCC), whose unit cell edge lengths are 3.5 Å and 3.0 Å respectively. Find the ratio of the densities of FCC and BCC.

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

Arrange the following oxyacids of chlorine – HClO, HClO2, HClO3, and HClO4 with respect to Increasing order of thermal stability.

Chapter: [7.03] Group 17 Elements
Concept: P - Block Group 17 Elements - Chlorine

Arrange the following oxyacids of chlorine – HClO, HClO2, HClO3, and HClO4 with respect to Increasing order of oxidizing power.

Chapter: [7.03] Group 17 Elements
Concept: P - Block Group 17 Elements - Chlorine
[7]4.2

An organic substance (M = 169 gram mol–1) is dissolved in 2000 cm3 of water. Its osmotic pressure at 12°C was found to be 0.54 atm. If R = 0.0821 L atm K–1 mol–1, calculate the mass of the solute.

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

How many atoms constitute one unit cell of a face-centered cubic crystal?

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

Distinguish between isothermal process and adiabatic process.

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Concepts of System

Mention the names of various steps involved in the extraction of pure metals from their ores.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Electrochemical Principles of Metallurgy
[7]5 | Select and write the most appropriate answer from the given alternatives for each sub-question:
[1]5.1

In the following 

The compound ‘B’ is _______.
(A) Propan–1–amine

(B) Propan–2–amine

(C) Isopropylamine

(D) Dimethylamine

Chapter: [13.01] Amines
Concept: Classification of Amines
[1]5.2

The stability order for carbocation is _______.

(A) 2° > 3° > 1° 

(B) 3° > 2° > 1°

(C) 3° > 1° > 2°

(D) 1° > 3° > 2°

Chapter: [10.01] Haloalkanes
Concept: Chemical Reactions of Haloalkanes and Haloarenes - Reactions of Haloalkanes - Nucleophilic Substitution Reactions
[1]5.3

Effective atomic number rule is used to find _______.
(A) geometry of complex
(B) stability of complex
(C) number of isomers of complex
(D) number of possible ligands around metal ion in complex

Chapter: [9] Coordination Compounds
Concept: Coordination Compounds - Importance of Coordination Compounds

Effective atomic number rule is used to find _______.
(A) geometry of complex
(B) stability of complex
(C) number of isomers of complex
(D) number of possible ligands around metal ion in complex

Chapter: [9] Coordination Compounds
Concept: Coordination Compounds - Importance of Coordination Compounds
[1]5.4

Which one of the following ions is coloured?
(A) Sc3+

(B) Zn2+

(C) Ti4+

(D) V2+

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[1]5.5

When phenol is heated with conc. HNO3 in presence of conc. H2SO4 it yields _______.

(A) o-nitrophenol

(B) p-nitrophenol

(C) 2,4,6-trinitrophenol

(D) m-nitrophenol

Chapter: [11.02] Phenols
Concept: Phenols - Acidic Nature of Phenol
[1]5.6

The secondary structure of protein is determined by _______.

(A) co-ordinate bond

(B) ionic bond

(C) hydrogen bond

(D) covalent bond

Chapter: [14.02] Proteins
Concept: Proteins - Structure, Classification and Functions
[1]5.7

Ethylidene dichloride when boiled with aqueous solution of NaOH yields _______.

(A) formaldehyde

(B) acetaldehyde

(C) acetone

(D) ethyl methyl ketone

Chapter: [11.01] Alcohols
Concept: Alcohols, Phenols and Ethers - Nomenclature

Ethylidene dichloride when boiled with aqueous solution of NaOH yields _______.

(A) formaldehyde

(B) acetaldehyde

(C) acetone

(D) ethyl methyl ketone

Chapter: [11.02] Phenols
Concept: Alcohols, Phenols and Ethers - Nomenclature

Ethylidene dichloride when boiled with aqueous solution of NaOH yields _______.

(A) formaldehyde

(B) acetaldehyde

(C) acetone

(D) ethyl methyl ketone

Chapter: [11.03] Ethers
Concept: Alcohols, Phenols and Ethers - Nomenclature
[12]6 | Answer any SIX of the following:
[2]6.1

How is phenol prepared from cumene?

Chapter: [11.02] Phenols
Concept: Phenols - Methods of Preparation
[2]6.2

Write a note on self oxidation-reduction reaction of aldehyde with suitable example.

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Other Reactions
[2]6.3

Explain basic nature of amines.

Chapter: [13.01] Amines
Concept: Structure of Amines
[2]6.4

Explain the term Antiseptics

Chapter: [16.01] Chemicals in Medicines
Concept: Drugs and Their Classification
[2]6.5

What happens when glucose is treated with hydroxylamine?

Chapter: [14.01] Carbohydrates
Concept: Carbohydrates - Structures of Glucose

What happens when glucose is treated with hydrogen cyanide?

Chapter: [14.01] Carbohydrates
Concept: Carbohydrates - Structures of Glucose
[2]6.6

Draw structure of dichromate ion

Chapter: [8.01] D-block Elements
Concept: D-block Elements - Some Important Compounds of Transition Elements

Draw structure of chromate ion

Chapter: [8.01] D-block Elements
Concept: D-block Elements - Some Important Compounds of Transition Elements
[2]6.7

How is terylene prepared?

Chapter: [15] Polymers
Concept: Polymers - Nylon 66
[2]6.8

Identify A and B in the following reaction:

`CH_3-Br+Mg"dry eather"/""A+CO_2"dry ether"/(H^+/(H_2O))B+Mg(Br)OH`

Chapter: [10.02] Haloarenes
Concept: Introduction of Haloalkanes and Haloarenes

Identify A and B in the following reaction:

`CH_3-Br+Mg"dry eather"/""A+CO_2"dry ether"/(H^+/(H_2O))B+Mg(Br)OH`

Chapter: [10.01] Haloalkanes
Concept: Introduction of Haloalkanes and Haloarenes
[3]7 | Answer any THREE of the following:
[3]7.1

How ligands are classified? Explain with suitable examples.

Chapter: [9] Coordination Compounds
Concept: Coordination Compounds - Introduction
[3]7.2

What is lanthanoid contraction?

Chapter: [8.02] F-block Elements
Concept: F-block Elements - The Lanthanoids

Explain, why lanthanum (Z = 57) forms La3+ ion, while cerium (Z = 58) forms Ce4+ ion?

Chapter: [8.02] F-block Elements
Concept: F-block Elements - The Lanthanoids
[3]7.3

What is the action of phenyl hydrazine on propanone?

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Preparation of Aldehydes and Ketones

What is the action of Zn – Hg / conc. HCl on propanone?

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Preparation of Aldehydes and Ketones

What is the action of Sodium bisulphite on propanone?

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Preparation of Aldehydes and Ketones
[3]7.4

Define enzymes.

Chapter: [14.02] Proteins
Concept: Enzymes

How is peptide linkage formed?

Chapter: [14.02] Proteins
Concept: Proteins - Peptide
[7]8 | Answer any ONE of the following:
[7]8.1

How is nitroethane converted into ethylamine.

Chapter: [11.03] Ethers
Concept: Ethers - Physical and Chemical Properties of ether

How is nitroethane converted into N-ethylhydroxylamine

Chapter: [11.03] Ethers
Concept: Ethers - Physical and Chemical Properties of ether

How is nitroethane converted into acetic acid

Chapter: [11.03] Ethers
Concept: Ethers - Physical and Chemical Properties of ether

Write names and chemical formulae of monomers used in preparing Buna-N.

Chapter: [15] Polymers
Concept: Types of Polymerisation Reactions - Rubber

What is a soap ?

Chapter: [16.03] Cleansing Agents
Concept: Cleansing Agents - Soaps

How soap is prepared?

Chapter: [16.03] Cleansing Agents
Concept: Cleansing Agents - Soaps
[7]8.2

How will you prepare ethanol, propan-2-ol and 2-methylpropan-2-ol from Grignard’s reagent?

Chapter: [11.01] Alcohols
Concept: Alcohols - Methods of Preparation

Explain  Optical activity

Chapter: [9] Coordination Compounds
Concept: Werner’S Theory of Coordination Compounds

Explain optical activity of lactic acid

Chapter: [9] Coordination Compounds
Concept: Werner’S Theory of Coordination Compounds
S