HSC Science (Electronics) 12th Board ExamMaharashtra State Board
Account
It's free!

User


Login
Create free account


      Forgot password?
Share
Notifications

View all notifications
Books Shortlist
Your shortlist is empty

Question Paper Solutions - Chemistry 2012 - 2013 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

In body centred cubic structure the space occupied is about

(A) 68%                                                     (B) 53%

(C) 38%                                                     (D) 32%

Chapter: [1] Solid State
Concept: Packing Efficiency - Efficiency of Packing in Body-centred Cubic Structures
[1]1.2

For a gaseous reaction the unit of rate of reaction is

(A) L atm s-1

(B) atm mol-1 s-1

(C) atm s1

(D) mol s

Chapter: [5] Chemical Kinetics
Concept: Rate of a Chemical Reaction
[1]1.3

Which of the following compounds contain S = O as well as S = S bonds?

(A) Sulphuric acid

(B) Thiosulphuric acid

(C) Sulphurous acid

(D) Thiosulphurous acid

 

Chapter: [7.02] Group 16 Elements
Concept: P - Block Group 16 Elements - Compounds of Sulphur
[1]1.4

Which of the following solutions shows maximum depression in freezing point?

(A) 0.5 M Li2SQ4

(B) 1 M NaCl

(C) 0.5 M A12(SO4)3

(D) 0.5 MBaC12

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Depression of Freezing Point
[1]1.5

For a chemical reaction ΔS=0.035 kJ/k and ΔH=20kJ.

(A) 5.14 K

(B) 57.14 K

(C) 571.4 K

(D) 5714.0 K

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Internal Energy and Enthalpy
[1]1.6

The standard e.m.f of the following cell is 0.463 V

`Cu|Cu_(1m)^(++)`

What is the standard potential of Cu electrode?

(A) 1.137 V

(B) 0.337 V

(C) 0.463 V

(D) - 0.463 V

Chapter: [4] Electrochemistry
Concept: Galvanic Cells - Introduction
[1]1.7

Fe2O3 is reduced to spongy iron near the top of blast furance by

(A) H2

(B) CaO

(C) SiO2

(D) CO

Chapter: [6] General Principles and Processes of Isolation of Elements
Concept: Occurrence of Metals
[12]2 | (A) Answer any SIX of the following
[2]2.1

Distinguish between crystalline solid and amorphous solid

Chapter: [1] Solid State
Concept: Amorphous and Crystalline Solids
[2]2.2

State Kohlrausch Law

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

Write mathematical expression of molar conductivity of the given solution at infinite dilution.

Chapter: [4] Electrochemistry
Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
[2]2.3

Write cell reaction in lead storage battery during discharge.

Chapter: [4] Electrochemistry
Concept: Batteries - Primary Batteries
[2]2.4

Draw structure and write geometry of PCl3 and PCl5.

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Compounds of Phosphorus
[2]2.5

Prove that ΔH=ΔU+ΔnRT. what is the condition under which ΔU=ΔH?

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - First Law of Thermodynamics
[2]2.6

Mention names and formulae of two ores of alumunium.

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

Derive the relationship between relative lowering of vapour pressure and molar mass of nonvolatile solute.

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Relative Lowering of Vapour Pressure
[2]2.8

What is pseudo first order reaction? Give one· example of it.

Chapter: [5] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction
[9]3 | Answer any THREE of the following:
[3]3.1

Calculate the mole fraction and molality of HNO3 in solution contaning 12.2%HNO3 (Given atomic mases:H=1, N=13,O=16)

Chapter: [2] Solutions and Colligative Properties
Concept: Colligative Properties and Determination of Molar Mass - Introduction
[3]3.2
 

Consider the reaction

`3I_((aq))^-) +S_2O_8^(2-)->I_(3(aq))^-) + 2S_2O_4^(2-)`

At particular time t, `(d[SO_4^(2-)])/dt=2.2xx10^(-2)"M/s"`

What are the values of the following at the same time?

a. `-(d[I^-])/dt`

b. `-(d[S_2O_8^(2-)])/dt`

c. `-(d[I_3^-])/dt`

 

 
Chapter: [5] Chemical Kinetics
Concept: Temperature Dependence of the Rate of a Reaction
[3]3.3

300 M mol of perfect gas occupies 13 L at 320 K. Calculate the work done in joules when the gas expands-

(a) isothermally against a Constant external pressure of 0.20atm.

(b) isothermal and reversible process.

(c) into vaccum until the volume of gas is increased by 3L (R=8.314J mol-1 K-1)

Chapter: [3] Chemical Thermodynamics and Energetic
Concept: Chemical Thermodynamics and Energetic - Work, Heat, Energy, Extensive and Intensive Properties
[3]3.4

What is the action of Excess of air on ammonia?

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Ammonia

What is the action of Excess of chlorine on ammonia?

 

 

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Ammonia

What is the action of Na Metal on ammonia? 

Chapter: [7.01] Group 15 Elements
Concept: P - Block Group 15 Elements - Ammonia
[7]4 | Answer any one of the following
[7]4.1
[2]4.1.1 | Explain with reason sign conventions of ΔS in the following reactions:
[1]4.1.1.1

Explain with reason sign conventions of ΔS in the following reaction

N2(g)+3H2(g)→2NH3(g)

Chapter: [1] Solid State
Concept: Number of Atoms in a Unit Cell
[1]4.1.1.2

Explain with reason sign conventions of ΔS in the following reaction

CO2(g) → CO2(g)

Chapter: [1] Solid State
Concept: Number of Atoms in a Unit Cell
[2]4.1.2 | Explain the following terms
[1]4.1.2.1

Explain the following term

Smelting

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]4.1.2.2

Explain the following term

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
[3]4.1.3

Gold occurs as face centred cube and has a density of 19.30 kg dm-3. Calculate atomic radius of gold (Molar mass of Au=197)

Chapter: [1] Solid State
Concept: Number of Atoms in a Unit Cell
[7]4.2

a. Explain the trends in the following properties with reference to group 16:

1 Atomic radii and ionic radii

2 Density

3 ionisation enthalpy

4 Electronegativity

b. In the electolysis of AgNO3 solution 0.7g of Ag is deposited after a certain period of time. Calulate the quantity of electricity required in coulomb. (Molar mass of Ag is 107.9g mol-1)

 

Chapter: [7.02] Group 16 Elements
Concept: Concept of Group 16 Elements

Define Osmosis

Chapter: [7.02] Group 16 Elements
Concept: Concept of Group 16 Elements
[7]5 | Select and write the most appropriate answer from the given alternatives for each sub-question:
[1]5.1

ln which pair highest oxidation states of transition metals are found:

(A) nitriles and chlorides

(B) fluorides and chlorides

(C) fluorides and oxides

(D) nitriles and oxides

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[1]5.2

which of the following carbocations is least stable?

(A) 

(B)

(C)

(D)

 

 

Chapter: [10.02] Haloarenes
Concept: Haloalkanes and Haloarenes - Nature of C-x Bond

which of the following carbocations is least stable?

(A) 

(B)

(C)

(D)

 

 

Chapter: [10.01] Haloalkanes
Concept: Haloalkanes and Haloarenes - Nature of C-x Bond
[1]5.3

Compound having general formula is called

(A) diester

(B) acid anhydride

(C) hemiacetal

(D) acetal

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Nomenclature
[1]5.4
 

The complex ion `[Co(H_2O)_5 (ONO)]^(2+) `

(A) linkage isomer

(B) ionisation isomer

(C) co-ordination isomer

(D) geometrical isomer

 
Chapter: [9] Coordination Compounds
Concept: Isomerism in Coordination Compounds - Structural Isomerism
[1]5.5

Inflammation af tongue is due to the deficiency of:

(A) Vitamin B1

(B) Vitamin B2

(C) Vitamin B5

(D) Vitamin B6

Chapter: [14.03] Vitamins
Concept: Vitamins - Important Vitamins, Their Sources and Their Deficiency Diseases
[1]5.6

Identify the compound 'B' in the following series of reaction:

(A) n-propyl chloride

(B) Propanamine

(C) n-propyl alcohol

(D) Isoproply alcohol

Chapter: [11.01] Alcohols
Concept: Alcohols - Methods of Preparation
[1]5.7

Which of the following reagents is best for the following conversion?

(A) LiAlH4

(B) 

(C) H2/Ni, 453 K

(D) Zn-Hg+HCl(con)

Chapter: [11.01] Alcohols
Concept: Alcohols - Methods of Preparation
[12]6 | Answer any SIX ofthe following
[2]6.1

Calculate magnetic moment of  `Fe_((aq))^(2+) ion (Z=26).`

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

How is ethanol prepared from methanal by using Grignard reagent?

Chapter: [11.01] Alcohols
Concept: Alcohols - Methods of Preparation
[2]6.3

Write the chemical reaction to prepare novolac polymer.

Chapter: [15] Polymers
Concept: Polymers - Some Important Polymers
[2]6.4

Why does p-nitrochlorobenzene undergo displacement reactions readily with attack of nucleophilic HOΘ ion?

Chapter: [10.02] Haloarenes
Concept: Haloarenes - Nucleophilic Substitution
[2]6.5

What is the action of bromine in alkaline medium on

i. CH3CH2NO2

ii. 

Chapter: [10.01] Haloalkanes
Concept: Methods of Preparation of Haloalkanes and Haloarenes
[2]6.6

Define antioxidants?

Chapter: [16.02] Chemicals in Food
Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
[2]6.7

How is 4-methylpent-3-en-2-one obtained from propan-2-one?

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Reactivity of Alpha Hydrogen in Aldehydes
[2]6.8

What are hormones?

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

Write the structure of simple triglycerides.

Chapter: [14.02] Proteins
Concept: Proteins - Structure, Classification and Functions
[9]7 | Answer any THREE of the following
[3]7.1

Write the different oxidation states of manganese.

Chapter: [8.01] D-block Elements
Concept: Electronic Configurations of the D-block Elements

Why +2 oxidation state of manganese is more stable?

Chapter: [8.01] D-block Elements
Concept: General Properties of the Transition Elements (D-block)
[3]7.2

How are the following compounds prepared?

benzaldehyde from benzene

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

How are the following compounds prepared?

acetophenone from benzene

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

How are the following compounds prepared?

benzaldehyde from benzoyl chloride

Chapter: [12.01] Aldehydes and Ketones
Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Nucleophilic Addition Reactions
[3]7.3

Write the structure of a nucleotide

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

Write the structure of a nucleoside

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

Define complex lipids

Chapter: [14.02] Proteins
Concept: Proteins - Structure, Classification and Functions
[3]7.4

Write the fomulae of the following compounds

Sodium hexanitrito- N - cobaltate (III)

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

Write the fomulae of the following compounds :

Tetraaquodichlorochromium (III) chloride

 

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

Write the fomulae of the following compounds

Potassium tetracyanoaurate (III) ion

Chapter: [9] Coordination Compounds
Concept: Nomenclature of Coordination Compounds - Formulas of Mononuclear Coordination Entities
[7]8 | Answer any ONE of the following
[7]8.1

Explain the following term: Homopolymers

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

Explain the following term: Elastomers

Chapter: [15] Polymers
Concept: Introduction of Polymers

Explain the mechanism of cleansing action of soaps.

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

Write balanced chemical equations for the action of phosphorous trichloride on propan-2-ol

Chapter: [15] Polymers
Concept: Introduction of Polymers

Write balanced chemical equations for the action of hydrogen bromide on styrene in the presence of a peroxide

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

Write balanced chemical equations for the action of methyl bromide on silver propanoate

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

Write a short note on Hoffmann bromamide degradation.

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

Explain the mechanism of action of hydroiodic acid on 3-methylbutan-2-ol.

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

Mention 'two' uses of propan-2-one.

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