HSC Science (General) 12th Board ExamMaharashtra State Board
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Question Paper Solutions - Chemistry 2015 - 2016 HSC Science (General) 12th Board Exam

CHEMISTRY

(PHYSICAL AND INORGANIC CHEMISTRY)

Notes:

  1. All questions are compulsory.
  2. Answers of both the sections should be written in same answer book.
  3. Draw well labelled diagrams and write balanced equations wherever necessary.
  4. Figures to the right indicate full marks.
  5. Use of logarithmic table is allowed.
  6. Every new question must be started on a new page.

 


Marks: 70
[12]1 | Answer any six of the following
[2]1.1

What is ferromagnetism?

Chapter: [1] Solid State
Concept: Magnetic Properties

Iron (z=26) is highly ferromagnetic. Explain.

Chapter: [1] Solid State
Concept: Magnetic Properties
[2]1.2

Define boiling point

Chapter: [2] Solutions and Colligative Properties
Concept: Types of Solutions

Write the formula to determine the molar mass of a solute using freezing point depresssion method.

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Depression of Freezing Point
[2]1.3 | Write mathematical equation of first law of thermodynamics
[1]1.3.1

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
[1]1.3.2

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
[2]1.4

Explain a graphical method to determine activation energy of a reaction.

Chapter: [5] Chemical Kinetics
Concept: Temperature Dependence of the Rate of a Reaction
[2]1.5 | Write the names and chemical formulae
[1]1.5.1

Write the names and chemical formulae of any one ore of iron.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[1]1.5.2

Write the names and chemical formulae of any one ore of zinc.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[2]1.6

Define enthalpy of sublimation.

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

How is enthalpy of sublimation related to enthalpy of fusion and enthalpy of vaporization?

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Internal Energy and Enthalpy
[2]1.7

What are Ellingham's diagrams? Write 2 features of it.

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

Write features of Ellingham's diagrams

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Thermodynamic Principles of Metallurgy
[9]2 | Answer any 3 of the following
[3]2.1

Silver crystallises in FCC structure. If density of silver is 10.51 gcm-3, calculate the volume of unit cell.

[Atomic mass of slive (Ag) = 108 gm-1]

Chapter: [1] Solid State
Concept: Calculations Involving Unit Cell Dimensions
[3]2.2

The vapour pressure of pure benzene is 640mm og Hg. 2.175×10-3kg of non-vloatile solute is added to 39 gram of benzene the vapour pressure of solution is 600mm of HG. Calculate molar mass of solute.

[C = 12, H = 1]

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Introduction
[3]2.3

Calculate C-Cl bond enthalpy from following reaction:

CH3Cl(g) + Cl2(g) → Ch2Cl2(g) + HCl(g) ΔH° = -104KJ

If C-H, Cl-Cl and H-Cl bond enthalpies are 414, 243 and 431 KJ-Mol-1 respectively.

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Enthalpy of Bond Dissociation
[3]2.4

Define cell constant.

Chapter: [4] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Introduction

Draw a neat and well labelled diagram of primary reference electrode.

Chapter: [4] Electrochemistry
Concept: Galvanic Cells - Introduction
[7]3 | Answer any ONE of the following
[7]3.1
[2]3.1.1

Write four points of differences between properties of nitrogen and other elements of group 15.

Chapter: [7.01] Group 15 Elements
Concept: Concept of Group 15 Elements
[1]3.1.2

Explain the structure of ClF3

Chapter: [7.03] Group 17 Elements
Concept: P - Block Group 17 Elements - Interhalogen Compounds
[3]3.1.3

Conductivity of a solution is 6.23 x 10-5  Ω-1cm-1 and its resistance is 13710Ω. If the electrodes are 0.7cm apart, calculate the cross-sectional area of electrode.

Chapter: [4] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Introduction
[1]3.1.4

Why is molality of a solution independent of temperature?

Chapter: [2] Solutions and Colligative Properties
Concept: Expressing Concentration of Solutions
[7]3.2
[1]3.2.1

What are neutral oxides?

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Simple Oxides
[2]3.2.2

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
[1]3.2.3

Define "Molar conductivity".

Chapter: [4] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
[1]3.2.4

Define "zero order reaction".

Chapter: [5] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[2]3.2.5

In a first order reaction x → y, 40% of the given sample of compound remains unreacted in 45 minutes. Calculate rate constant of the reaction.

Chapter: [5] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction

Define "zero order reaction".

Chapter: [5] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[7]4 | Select and write the most appropriate answer from the given alternatives for each sub-question
[1]4.1

The molecular formula H2S2O2 represents which oxoacid?

  • Hydrosulphurous acid
  • Thiosulphurous acid
  • Sulphuric acid
  • Pyrosulphurous acid
Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Oxoacids of Sulphur
[1]4.2

Iodine exists as

  • polar molecular solid
  • ionic solid
  • nonpolar molecular solid
  • hydrogen bonded molecular solid
Chapter: [7.03] Group 17 Elements
Concept: P - Block Group 17 Elements - Concept of Group 17 Elements
[1]4.3

Absolute entropies of solids, liquids and gases can be determined by

  • Measuring heat capacity of substance at various temperatures
  • Subtracting standard entropy of reactants from products
  • Measuring vibrational motion of molecules
  • Using formula ΔS° = ST° - SO°
Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Work, Heat, Energy, Extensive and Intensive Properties
[1]4.4

The determination of molar mass from elevation in boiling point is called as

  • cryoscopy
  • colorimetry
  • ebullioscopy
  • spectroscopy
Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Introduction
[1]4.5

The process of leaching alumina, using sodium carbonate is called

  • Bayer's process
  • Decomposition
  • Cyanide process
  • Hall's process
Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[1]4.6

On calculating the strength of current in amperes if a charge of 840C (coulomb) passes through an electrolyte in 7 minutes, it will be

  • 1
  • 2
  • 3
  • 4
Chapter: [4] Electrochemistry
Concept: Electrolytic Cells and Electrolysis - Introduction
[1]4.7

A → B is a first order reaction with rate 6.6 × 10-5m-s-1. When [A] is 0.6m, rate constant of the reaction is

  • 1.1 × 10-5s-1
  • 1.1 × 10-4s-1
  • 9 × 10-5s-1
  • 9 × 10-4s-1
Chapter: [5] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[12]5 | Answer any SIX of the following
[2]5.1

Why is Sc3+ colourless while Ti3+ coloured? (Atomic number Sc = 21, Ti =22)

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[2]5.2

Illustrate with example, the difference between a double salt and a co-ordination compound

Chapter: [9] Coordination Compounds
Concept: Coordination Compounds - Introduction
[2]5.3

How is chlorobenzene prepared from aniline?

Chapter: [13.01] Amines
Concept: Amines - Chemical Reactions of Amines - Electrophilic Substitution

How is chlorobenzene converted into diphenyl/biphenyl?

Chapter: [10.02] Haloarenes
Concept: Haloarenes - Reaction with Metals
[2]5.4

What is metamerism? 

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

What is metamerism? 

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

What is metamerism? 

Chapter: [11.03] Ethers
Concept: Alcohols, Phenols and Ethers - Nomenclature

Explain metamerism with suitable examples of ethers

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

Explain metamerism with suitable examples of ethers

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

Explain metamerism with suitable examples of ethers

Chapter: [11.03] Ethers
Concept: Alcohols, Phenols and Ethers - Nomenclature
[2]5.5

What are ketones? 

Chapter: [12.01] Aldehydes and Ketones
Concept: Introduction of Aldehydes, Ketones and Carboxylic Acids

How are ketones classified?

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Nomenclature
[2]5.6

How is 1-nitropropane prepared from suitable oxime?

Chapter: [12.02] Carboxylic Acids
Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of O-H Bond

How are  2 - nitropropane prepared from suitable oxime?

Chapter: [12.02] Carboxylic Acids
Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of O-H Bond
[2]5.7

Define antioxidants?

Chapter: [16.02] Chemicals in Food
Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives

Draw structure of BHT.

Chapter: [16.02] Chemicals in Food
Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
[2]5.8

Define carbohydrates.

Chapter: [14.01] Carbohydrates
Concept: Introduction of Carbohydrates

Write the reaction for the preparation of Nylon-6.

Chapter: [15] Polymers
Concept: Polymers - Nylon 6
[9]6 | Answer any THREE of the following
[3]6.1

What are f-block elements? 

Chapter: [8.02] F-block Elements
Concept: F-block Elements - General Indroduction

Distinguish between lanthanoid and actinoids.

Chapter: [8.02] F-block Elements
Concept: F-block Elements - The Actinoids
[3]6.2
[1]6.2.1

Explain  Optical activity

Chapter: [9] Coordination Compounds
Concept: Werner’S Theory of Coordination Compounds
[1]6.2.2

Explain  Ligand

Chapter: [9] Coordination Compounds
Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
[1]6.2.3

Explain Interstitial compounds

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[3]6.3

Write the formula of Tetraminodichloroplatinum (IV) chloridex.

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

 How is propene converted into 1- bromopropane and 2 - bromopropane?

Chapter: [10.01] Haloalkanes
Concept: Methods of Preparation of Haloalkanes and Haloarenes
[3]6.4

What are broad-spectrum antibiotics?

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

How are polythene and neoprene prepared?

Chapter: [15] Polymers
Concept: Types of Polymerisation Reactions - Addition Polymerisation Or Chain Growth Polymerisation
[7]7 | Answer any ONE of the following :
[7]7.1

Explain the mechanism of esterification

Chapter: [12.02] Carboxylic Acids
Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of C-OH Bond

Write the reactions involved in dehydration of 1°, 2° and 3° alcohols.

Chapter: [11.01] Alcohols
Concept: Alcohols - Mechanism of Dehydration of Alcohols
[7]7.2

What are vitamins?

Chapter: [14.03] Vitamins
Concept: Introduction of Vitamins

Name any two diseases caused by deficiency of Vitamin A

Chapter: [14.03] Vitamins
Concept: Vitamins - Important Vitamins, Their Sources and Their Deficiency Diseases

Write the structure of a nucleoside

Chapter: [14.04] Nucleic Acids
Concept: Introduction of Nucleic Acids

Write the structure of a nucleotide

Chapter: [14.04] Nucleic Acids
Concept: Introduction of Nucleic Acids

How are 1 - nitropropane, 2-nitropropane and 2-methyl 2- nitropropane are distinguished from each other using nitrous acid?

Chapter: [13.01] Amines
Concept: Amines - Identification of Primary, Secondary and Tertiary Amines
[7]8 | Select and write the most appropriate answers from the given alternatives
[1]8.1

The preparation of alkyl fluoride from alkyl chloride, in presence of metallic fluorides is known as

(a) Williamson’s reaction                                 

(b) Finkelstein reaction

(c) Swarts reaction

(d) Wurtz reaction

Chapter: [10.01] Haloalkanes
Concept: Methods of Preparation of Haloalkanes and Haloarenes
[1]8.2

Identify the weakest acidic compound amongst the following

(a) p-nitrophenol                 

(b) p-chlorophenol

(c) p-cresol                         

(d) p-raminophenol

Chapter: [11.02] Phenols
Concept: Phenols - Physical and Chemical Properties
[1]8.3

On acid hydrolysis, propane nitrile gives

(a) propanal                       

(b) acetic acid

(c) propionamide

(d) propanoic acid

Chapter: [12.02] Carboxylic Acids
Concept: Carboxylic Acids - Methods of Preparation of Carboxylic Acids
[1]8.4

Which of the following amines yields foul smelling product with holoform and alcoholic KOH?

(a)    Ethyl amine                   

(b)   Diethyl amine

(c)    Triethyi amine               

(d)  Ethyl methyl amine

Chapter: [13.01] Amines
Concept: Amines - Chemical Reactions of Amines - Carbylamine Reaction
[1]8.5

Which of the following NOT present in DNA?

(a)  adenine                        

(b) Guanine

(c) Thymine

(d) Uracil

Chapter: [14.04] Nucleic Acids
Concept: Introduction of Nucleic Acids
[1]8.6

Amongst the followings, identify a copolymer?

(a) Orion                            

(b) PVC

(c) PHBV

(d) Teflon

Chapter: [15] Polymers
Concept: Types of Polymerisation Reactions - Copolymerisation
[1]8.7

Phenelzine is used as an

(a)  analgesic                      

(b) antiseptic

(c) antipyretic

(d) antidepressant

Chapter: [11.02] Phenols
Concept: Phenols - Uses of Phenols
S