HSC Science (Electronics) 12th Board ExamMaharashtra State Board
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Question Paper Solutions - Chemistry 2017 - 2018 HSC Science (Electronics) 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

The process in which the value of ΔU = 0 is __

(a) Adiabatic

(b) Isothermal

(c) Isobaric

(d) Isochoric

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Types of Systems
[1]1.2

An ionic crystal lattice has `r^+/r` radius ratio of 0.320, its coordination number is __

(a) 3

(b) 4

(c) 6

(d) 8

Chapter: [1] Solid State
Concept: Crystal Lattices and Unit Cells - Introduction
[1]1.3

In the hydrogen-oxygen fuel cell, the carbon rods are immersed in the hot aqueous solution of __

(a) KCl

(b) KOH

(c) H2SO4

(d) NH4Cl

Chapter: [4] Electrochemistry
Concept: Batteries - fuel cell
[1]1.4

The chemical formula of willemite is __

(a) ZnS

(b) ZnCO3

(c) ZnO

(d) Zn2SiO4

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[1]1.5

The oxidation state of nitrogen in dinitrogen trioxide is ____

(a) + 1

(b) + 2

(c) + 3

(d) + 4

Chapter: [7.01] Group 15 Elements
Concept: Concept of Group 15 Elements
[1]1.6

Which of the following 0.1 M will aqueous solutions exert highest osmotic pressure?

(a) `Al_2(SO_4)_3`

(b) `Na_2SO_4`

(c) `MgCl_2`

(d) KCl

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Osmosis and Osmotic Pressure
[1]1.7

The half-life period of zero order reaction A → product is given by

(a) `([A]_0)/k`

(b) `0.693/k`

(c) `[A]_0/(2k)`

(d) `(2[A]_0)/k`

Chapter: [5] Chemical Kinetics
Concept: Integrated Rate Equations - Half-life of a Reaction
[12]2 | Attempt Any Six of Following
[2]2.1

Derive the relation between the elevation of boiling point and molar mass of solute.

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Elevation of Boiling Point
[2]2.2

State Third law of thermodynamics

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

Give two uses of the Third law of thermodynamics.

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Second and Third Law of Thermodynamics
[2]2.3

Draw a neat and labelled diagram of the lead storage battery.

Chapter: [4] Electrochemistry
Concept: Galvanic Cells - Introduction
[2]2.4

Explain Ionic solids are hard and brittle.

Chapter: [1] Solid State
Concept: Classification of Crystalline Solids
[2]2.5

A certain reaction occurs in the following steps -

`Cl_(g) + O_(3(g)) -> ClO_((g)) + O_(2(g))`

`ClO_((g)) + O_((g)) -> Cl_((g)) + O_(2(g))`

a) What is the molecularity of each of the elementary steps?

b) Identify the reaction intermediate and write the chemical equation for overall reaction.

Chapter: [5] Chemical Kinetics
Concept: Rate of a Chemical Reaction
[2]2.6

Define Semipermeable membrane

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

Define Reference electrode

Chapter: [4] Electrochemistry
Concept: Galvanic Cells - Introduction
[2]2.7

What is the action of chlorine on CS2

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

What is the action of chlorine on Excess NH3

Chapter: [7.03] Group 17 Elements
Concept: P - Block Group 17 Elements - Chlorine
[2]2.8

Write the chemical equations involved in van Arkel method for refining zirconium metal.

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Refining
[9]3 | Answer any THREE of the following
[3]3.1

Write balanced chemical equations for Phosphorus reacts with magnesium

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Compounds of Phosphorus

Write balanced chemical equations for Flowers of sulphur boiled with calcium hydroxide

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Compounds of Phosphorus

Write balanced chemical equations for Action of ozone on hydrogen peroxide.

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Compounds of Phosphorus
[3]3.2

The density of iron crystal is 8.54-gram cm–3. If the edge length of the unit cell is 2.8 A° and atomic mass is 56-gram mol–1, find the number of atoms in the unit cell.  (Given: Avogadro's number = 6.022x1023,1A° = 1x10-8 cm)

Chapter: [1] Solid State
Concept: Concept of Close Packed Structures
[3]3.3

How many faradays of electricity are required to produce 13 gram of aluminium from aluminium chloride solution? (Given: Molar mass of Al = 27.0-gram mol–1)

Chapter: [4] Electrochemistry
Concept: Electrolytic Cells and Electrolysis - Introduction
[3]3.4

Calculate the internal energy at 298K for the formation of one mole of ammonia, if the enthalpy change at constant pressure is – 42.0 kJ mol-1.

(Given: R = 8.314 J K-1 mol-1)

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics
[7]4 | Attempt Any One
[7]4.1

Define the Enthalpy of atomization

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

Define Enthalpy of vaporization

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

Draw the structure of IF7. Write its geometry and the type of hybridization.

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

State Henry’s law.

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

22.22 gram of urea was dissolved in 300 grams of water. Calculate the number of moles of urea and molality of the urea solution. (Given: a Molar mass of urea = 60 gram mol-1)

Chapter: [2] Solutions and Colligative Properties
Concept: Expressing Concentration of Solutions
[7]4.2

What is the action of carbon on the following metal oxides:

Fe2O3 in the blast furnace

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

What is the action of carbon on the following metal oxides :

ZnO in the vertical retort furnace

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

Write the molecular and structural formulae of Thiosulphuric acid

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Compounds of Sulphur

Write the molecular and structural formulae of Dithionous acid

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Oxoacids of Sulphur

The reaction A + B → products is first order in each of the reactants

1) How does the rate of reaction change if the concentration of A is increased by factor 3?

2) What is the change in the rate of reaction if the concentration of A is halved and concentration of B is doubled?

Chapter: [5] Chemical Kinetics
Concept: Rate of a Chemical Reaction
[7]5 | Select and write the most appropriate answer from the given alternatives for each sub-question:
[1]5.1

A polymer used in paints is

(a) Nomex

(b) Thiokol

(c) Saran

(d) Glyptal

Chapter: [15] Polymers
Concept: Introduction of Polymers
[1]5.2

The number of primary and secondary hydroxyl groups in ribose are -

(a) 1, 3

(b) 2, 3

(c) 3, 1

(d) 3, 2

Chapter: [14.01] Carbohydrates
Concept: Classification of Carbohydrates
[1]5.3

The ligand diethylene triamine is -

(a) monodentate

(b) bidentate

(c) tridentate

(d) tetradentate

Chapter: [9] Coordination Compounds
Concept: Bonding in Coordination Compounds - Introduction
[1]5.4

Propene on oxidation with diborane in presence of alkaline hydrogen peroxide gives

(a) propane-1- ol

(b) propane-2-ol

(c) allyl alcohol

(d) propane-1, 2-diol

 

Chapter: [11.01] Alcohols
Concept: Alcohols - Methods of Preparation
[1]5.5

Baeyer’s reagent is -'

(a) acidified potassium dichromate

(b) alkaline potassium dichromate

(c) alkaline potassium permanganate

(d) acidified potassium permanganate

Chapter: [8.01] D-block Elements
Concept: D-block Elements - General Indroduction
[1]5.6

Identify 'A' in the following reaction -

(a) 2- Bromo-2 methylbutane

(b) 1 -Bromo-2,2-dimethylpropane

(c) 1 - Bromo - 3 -methylbutane

(d) 1 - Bromo- 2 -methylpropane

Chapter: [10.01] Haloalkanes
Concept: Chemical Reactions of Haloalkanes and Haloarenes - Reactions of Haloalkanes - Nucleophilic Substitution Reactions
[1]5.7

An antifertility drug is -

(a) Novestrol

(b) Histamine

(c) Vernal

(d) Equanil

Chapter: [16.01] Chemicals in Medicines
Concept: Chemicals in Medicines - Antipyretic, Antimalarial and Antifertility
[12]6 | Answer any SIX of the following
[2]6.1

Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
 in basic medium.

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[2]6.2

Explain the geometry of `[Co(NH_3)_6]^(3+)` on the basis of hybridisation. (Z of Co = 27)

Chapter: [9] Coordination Compounds
Concept: Bonding in Coordination Compounds - Valence Bond Theory (VBT)
[2]6.3

Why ethanol has the higher boiling point than ethane?

Chapter: [11.01] Alcohols
Concept: Classification of Alcohols and Phenols
[2]6.4

Write only reactions for the preparation of benzophenone from benzonitrile.

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Preparation of Aldehydes and Ketones
[2]6.5

What is the action of p-toluenesulphonychloride on ethylamine and diethylamine?

Chapter: [13.01] Amines
Concept: Amines - Nomenclature
[2]6.6

What are amino acids?

Chapter: [14.02] Proteins
Concept: Proteins - Amino Acids

Write the correct reaction for formation of the peptide bond between amino acids

Chapter: [14.02] Proteins
Concept: Proteins - Amino Acids
[2]6.7

Explain the term Antiseptics

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

Define antioxidants?

Chapter: [16.02] Chemicals in Food
Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
[2]6.8

Explain only reaction mechanism for alkaline hydrolysis of tert-butyl bromide

Chapter: [10.02] Haloarenes
Concept: Haloarenes - Electrophilic Substitution Reactions
[9]7 | Answer any THREE of the following
[3]7.1

Complete and rewrite the balanced chemical equations

Chapter: [10.01] Haloalkanes
Concept: Haloalkanes and Haloarenes - Nomenclature

Complete and rewrite the balanced chemical equations

Chapter: [12.02] Carboxylic Acids
Concept: Carboxylic Acids - Nomenclature

Complete and rewrite the balanced chemical equations

Butanone + 2, 4-dinitro-phenylhydrazine 

Chapter: [12.02] Carboxylic Acids
Concept: Chemical Properties and Reactions of Carboxylic Acid
[3]7.2

How carbolic acid is prepared from benzene sulphonic acid?

Chapter: [11.02] Phenols
Concept: Phenols - Phenols

Write a chemical equation for the action of neutral ferric chloride on phenol.

Chapter: [11.01] Alcohols
Concept: Classification of Alcohols and Phenols
[3]7.3

Explain the preparation and uses of nylon-2-nylon-6.

Chapter: [15] Polymers
Concept: Polymers - Nylon 6
[3]7.4

How is glucose prepared from cane sugar?

Chapter: [14.01] Carbohydrates
Concept: Carbohydrates - Preparation of Glucose from Sucrose (Cane Sugar) and Starch

Write the formula of the complex copper (II) hexacyanoferrate (II).

Chapter: [14.01] Carbohydrates
Concept: Carbohydrates - Preparation of Glucose from Sucrose (Cane Sugar) and Starch
[7]8 | Attempt Any One
[7]8.1

What is Lanthanoid contraction?

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

Explain the cause of Lanthanoids contraction.

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

Draw the structures of chloroxylenol

Chapter: [16.01] Chemicals in Medicines
Concept: Chemicals in Medicines - Antiseptic and Disinfectants

Draw the structures of adenine.

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

How are ethylamine and ethyl methyl amine distinguished by using nitrous acid?

Chapter: [13.01] Amines
Concept: Amines - Nomenclature
[7]8.2

What is the action of the following reagents on ethanoic acid?

1) `LiAlH_4"/"H_3O^+`

2) `PCl_2 , "heat"`

3) `P_2O_5, "heat"`

 

 

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Nucleophilic Addition Reactions

Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :

Chapter: [13.01] Amines
Concept: Amines - Preparation of Amines

Write a short note on Hoffmann bromamide degradation.

Chapter: [13.01] Amines
Concept: Amines - Preparation of Amines
S