Share
Notifications

View all notifications

Chemistry 56/1/1 2018-2019 CBSE (Science) Class 12 Question Paper Solution

Login
Create free account


      Forgot password?
Chemistry [56/1/1]
Marks: 70Academic Year: 2018-2019
Date & Time: 13th March 2019, 10:30 am
Duration: 3h

I. All questions are compulsory  

II. Section A: Question no. 1 to 5 are very short-answer questions and carry 1 mark each.

III. Section B: Question no. 6 to 12 are short-answer questions and carry 2 marks each.  

IV. Section C: Question no. 13 to 24 are also short-answer questions and carry 3 marks each.  

V. Section 13: Question no. 25 to 27 are long-answer questions and carry 5 marks each.

VI. There is no overall choice. However, an internal choice has been provided in two questions of one mark, two questions of two marks, four questions of three marks and all the three questions of five marks weightage. You have to attempt only one of the choices in such questions.

VII. Use log tables if necessary. The use of calculators is not allowed. 


SECTION-A
[1]1

Out of NaCl and AgCl, which one shows Frenkel defect and why? 

Concept: Imperfections in Solids - Types of Point Defects - Stoichiometric Defects
Chapter: [1] Solid State
[1]2

Arrange the following in increasing order of boiling points:

(CH3)3 N, C2 H5 OH, C2 H5 NH2

Concept: Colligative Properties and Determination of Molar Mass - Elevation of Boiling Point
Chapter: [2] Solutions
[1]3
[1]3.1

Answer the following question.
Why are medicines more effective in the colloidal state?

Concept: Properties of Colloidal Solutions
Chapter: [5] Surface Chemistry
OR
[1]3.2

Answer the following question.
What is the difference between an emulsion and a gel?

Concept: Emulsions
Chapter: [5] Surface Chemistry
[1]4

What are ambident nucleophiles? Explain with an example.

Concept: Chemical Reactions of Haloalkanes and Haloarenes - Reactions of Haloalkanes - Nucleophilic Substitution Reactions
Chapter: [10] Haloalkanes and Haloarenes
[1]5
[1]5.1

Answer the following question.
What is the basic structural difference between glucose and fructose?

Concept: Carbohydrates - Structures of Glucose
Chapter: [14] Biomolecules
OR
[1]5.2

Answer the following question.
Write the products obtained after the hydrolysis of lactose.

Concept: Carbohydrates - Disaccharides - Sucrose, Maltose and Lactose
Chapter: [14] Biomolecules
SECTION B
[2]6
[2]6.1

Write a balanced chemical equation for the following process:
XeF2 undergoes hydrolysis.

Concept: Rate of a Chemical Reaction
Chapter: [4] Chemical Kinetics
OR
[2]6.2
[1]6.2.1

Arrange the following in the order of the property indicated against set :
H2O, H2S, H2Se, H2Te − increasing acidic character.

Concept: Concept of Group 16 Elements
Chapter: [7] P - Block Elements
[1]6.2.2

Arrange the following in order of the property indicated set.
HF, HCl, HBr, HI - decreasing bond enthalpy.

Concept: Concept of Group 16 Elements
Chapter: [7] P - Block Elements
[2]7

State Raoult’s law for a solution containing volatile components. Write two characteristics of the solution which obey Raoult’s law at all concentrations. 

Concept: Vapour Pressure of Liquid Solutions - Vapour Pressure of Liquid- Liquid Solutions
Chapter: [2] Solutions
[2]8

For a reaction
\[\ce{2H2O2->[I^-][Alkaline medium]2H2O + O2}\]

The Proposed mechanism is given below: 
(1) H2O2+I- → H2O+IO-(slow)
(2) H2O2+IO-→H2O+I-+O2(fast)

(i) Write the rate law for the reaction.
(ii) Write the overall order of a reaction.
(iii) Out of steps(1) and (2), which one is the rate-determining step? 

Concept: Catalyst - Effect of Catalyst on the Rate of Reaction
Chapter: [4] Chemical Kinetics
[2]9

Answer the following question.
When MnO2 is fused with KOH in the presence of KNO3 as an oxidizing agent, it gives a dark green compound (A). Compound (A) disproportionates in an acidic solution to give a purple compound (B).  An alkaline solution of compound (B) oxidizes KI to compound (C) whereas an acidified solution of compound (B) oxidizes KI to (D). Identify (A), (B), (C), and (D).

Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Chapter: [8] "D" and "F" Block Elements
[2]10
[2]10.1

Write IUPAC name of the complex [Pt(en)2Cl2]. Draw structures of geometrical isomers for this complex. 

Concept: Isomerism in Coordination Compounds - Structural Isomerism
Chapter: [9] Coordination Compounds
OR
[2]10.2
[1]10.2.1

Using IUPAC norms write the formula of Hexaamminecobalt (III) sulphate. 

Concept: Amines - Nomenclature
Chapter: [13] Organic Compounds Containing Nitrogen
[1]10.2.2

Using IUPAC norms write the formulae of  Potassium trioxalatochromate (III) 

Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Chapter: [8] "D" and "F" Block Elements
[2]11

Out of [CoF6]3- and [Co(en)3]3+, which one complex is
(i) paramagnetic
(ii) more stable
(iii) inner orbital complex and
(iv) high spin complex
(Atomic no. of Co = 27) 

Concept: Magnetic Properties
Chapter: [1] Solid State
[2]12
[1]12.1

Write structures of compounds A and B of the following reaction : 

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
[1]12.2

Write structures of compounds A and B of the following reaction : 

Concept: Definitions of Some Important Terms Pertaining to Coordination Compounds
Chapter: [9] Coordination Compounds
SECTION C
[3]13

The decomposition of NH3 on a platinum surface is a zero-order reaction. If the rate constant (k)  is 4 x 10-3 ms-1, how long will it take to reduce the initial concentration of NH3 from 0.1 M to 0.064 M?

Concept: Integrated Rate Equations - Zero Order Reactions
Chapter: [4] Chemical Kinetics
[3]14
[1]14.1

What is the role of activated charcoal in a gas mask? 

Concept: Types of Solutions
Chapter: [2] Solutions
[1]14.2

A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the solution represented? 

Concept: Properties of Colloidal Solutions
Chapter: [5] Surface Chemistry
[1]14.3

How does chemisorption vary with temperature?

Concept: Adsorption - Types of Adsorption
Chapter: [5] Surface Chemistry
[3]15

An element crystallizes in fcc lattice with a cell edge of 300 pm. The density of the element is 10.8 g cm-3. calculate the number of atoms in 108 g  of the element.

Concept: Calculations Involving Unit Cell Dimensions
Chapter: [1] Solid State
[3]16

A 4% solution(w/w) of sucrose (M = 342 g mol–1) in water has a freezing point of 271.15 K. Calculate the freezing point of 5% glucose (M = 180 g mol–1) in water.
(Given: Freezing point of pure water = 273.15 K) 

Concept: Colligative Properties and Determination of Molar Mass - Depression of Freezing Point
Chapter: [2] Solutions
[3]17
[2]17.1
[1]17.1.1

Name the method of refining which is Used to obtain semiconductor of high purity. 

Concept: Refining
Chapter: [6] General Principles and Processes of Isolation of Elements
[1]17.1.2

Name the method of refining which is Used to obtain low boiling metal.

Concept: Refining
Chapter: [6] General Principles and Processes of Isolation of Elements
[1]17.2

Write chemical reactions taking place in the extraction of copper from Cu2 S. 

Concept: Application of Thermodynamic Principles of Metallurgy
Chapter: [6] General Principles and Processes of Isolation of Elements
[3]18
[1]18.1

Give a reason for the following: 

Transition elements and their compounds act as catalysts.

Concept: General Properties of the Transition Elements (D-block)
Chapter: [8] "D" and "F" Block Elements
[1]18.2

Give a reason for the following: 

 E° value for (Mn2+|Mn) is negative whereas for  (Cu2+|Cu) is positive. 

Concept: Concept of Group 15 Elements
Chapter: [7] P - Block Elements
[1]18.3

Give a reason for the following: 

Actinoids show irregularities in their electronic configurations.

Concept: F-block Elements - The Actinoids
Chapter: [8] "D" and "F" Block Elements
[3]19
[3]19.1
[1]19.1.1

Write the structures of monomers used the following polymers: 
Nylon - 6, 6

Concept: Types of Polymerisation Reactions - Condensation Polymerisation Or Step Growth Polymerisation
Chapter: [15] Polymers
[1]19.1.2

Write the structures of monomers used the following polymers:
Glyptal

Concept: Polymers of Commercial Importance
Chapter: [15] Polymers
[1]19.1.3

Write the structures of monomers used the following polymers:
Buna S

Concept: Types of Polymerisation Reactions - Rubber
Chapter: [15] Polymers
OR
[3]19.2
[1]19.2.1

Is   a homopolymer or copolymer? Give reason. 

Concept: Types of Polymerisation Reactions - Copolymerisation
Chapter: [15] Polymers
[1]19.2.2

Write the monomers of the following polymer : 

Concept: Polymers - Some Important Polymers
Chapter: [15] Polymers
[1]19.2.3

What is the role of sulphur in the vulcanisation of rubber?

Concept: Types of Polymerisation Reactions - Rubber
Chapter: [15] Polymers
[3]20
[3]20.1
[1]20.1.1

What use of drugs is used in sleeping pills?

Concept: Drugs and Their Classification
Chapter: [16] Chemistry in Everyday Life
[1]20.1.2

What type of detergents are used in toothpaste? 

Concept: Cleansing Agents - Synthetic Detergents
Chapter: [16] Chemistry in Everyday Life
[1]20.1.3

Why the use of alitame as an artificial sweetener is not recommended? 

Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
Chapter: [16] Chemistry in Everyday Life
OR
[3]20.2
[1]20.2.1

Define Broad-spectrum antibiotics with a suitable example?

Concept: Drugs and Their Classification
Chapter: [16] Chemistry in Everyday Life
[1]20.2.2

Define disinfectants with a Suitable example?

Concept: Cleansing Agents - Synthetic Detergents
Chapter: [16] Chemistry in Everyday Life
[1]20.2.3

Define the following term with a suitable example: 
Cationic detergents

Concept: Cleansing Agents - Synthetic Detergents
Chapter: [16] Chemistry in Everyday Life
[3]21
[1]21.1

Out of (CH3)3 C-Br and (CH3)3 C-I, which one is more reactive towards SN1 and why? 

Concept: Chemical Reactions of Haloalkanes and Haloarenes - Reactions of Haloarenes - Nucleophilic Substitution
Chapter: [10] Haloalkanes and Haloarenes
[1]21.2

Write the product formed when p-nitro chlorobenzene is heated with aqueous  NaOH at 443K followed by acidification? 

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Other Reactions
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[1]21.3

Why dextro and laevorotatory isomers of Butan-2-ol are difficult to separate by fractional distillation? 

Concept: Physical Properties of Haloalkanes and Haloarenes
Chapter: [10] Haloalkanes and Haloarenes
[3]22

An aromatic compound 'A' on heating with Br2 and KOH forms a compound 'B' of molecular formula C6H7N which on reacting with CHCl3 and alcoholic KOH produces a foul-smelling compound 'C'. Write the structures and IUPAC names of compounds A, B, and C.

Concept: Diazonium Salts - Importance of Diazonium Salts in Synthesis of Aromatic Compounds
Chapter: [13] Organic Compounds Containing Nitrogen
[3]23
[3]23.1
[1]23.1.1

complete the following reaction: 

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Other Reactions
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[1]23.1.2

complete the following reaction:

\[\ce{(C6H5CH2)2Cd + 2CH3COCl}\]

Concept: Haloalkanes and Haloarenes - Nomenclature
Chapter: [10] Haloalkanes and Haloarenes
[1]23.1.3

complete the following reaction: 

\[\begin{array}{cc}
\phantom{...}\ce{CH3} \\
| \\
\phantom{.................}\ce{CH3-CH-COOH ->[(i) Br2/Red P4][(ii)H2O]}
\end{array}\]

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Other Reactions
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
OR
[3]23.2
[1]23.2.1

Write a chemical equation for the following reaction: 
Propanone is treated with dilute Ba( OH)2.

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Reactions Due to A-hydrogen
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[1]23.2.2

Write chemical equation of the following reaction : 
Acetophenone is treated with `("Zn"("Hg"))/"Conc.HCl"`.

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Reduction
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[1]23.2.3

Write chemical equations of the following reaction :
Benzoyl chloride is hydrogenated in the presence of `"Pd"/(BaSO_4)`

Concept: Aldehydes and Ketones - Chemical Reactions of Aldehydes and Ketones - Reactions Due to A-hydrogen
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[3]24
[3]24.1
[1]24.1.1

Differentiable between the following: 
Amylose and Amylopectin 

Concept: Carbohydrates - Structures of Glucose
Chapter: [14] Biomolecules
[1]24.1.2

Differentiate between the following :

Peptide linkage and Glycosidic linkage 

Concept: Proteins - Structure of Proteins
Chapter: [14] Biomolecules
[1]24.1.3

Differentiate between  the following :

 Fibrous proteins and Globular proteins 

Concept: Proteins - Structure of Proteins
Chapter: [14] Biomolecules
OR
[3]24.2
[1]24.2.1

Write a chemical reaction to show that the open structure of D-glucose contains the following : 

 Straight chain 

Concept: Polymers - Classification of Polymers Based on Structure
Chapter: [15] Polymers
[1]24.2.2

Write a chemical reaction to show that the open structure of D-glucose contains the following :  

Five alcohol groups

Concept: Physical and Chemical Properties of Alcohols and Phenols
Chapter: [11] Alcohols, Phenols and Ethers
[1]24.2.3

Write a chemical reaction to show that the open structure of D-glucose contains the following : 

 Aldehyde as a carbonyl group 

Concept: Aldehydes and Ketones - Structure of the Carbonyl Group
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
SECTION-D
[5]25
[5]25.1

E°cell for the given redox reaction is 2.71V
\[\ce{Mg_{(s)} +Cu^{2+}_{(0.01 M)}->Mg^{2+}_{(0.001M)}+Cu_{(s)}}\]
Calculate Ecell for the reaction. Write the direction of flow of current when an external opposite potential applied is 
(i) less than 2.71 V and
(ii) greater than 2.71 V 

Concept: Faraday’s Law of Induction
Chapter: [3] Electrochemistry
OR
[5]25.2
[2.5]25.2.1

A steady current of 2 amperes was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO4and ZnSO4 until 2.8g of Fe deposited at the cathode of cell X. How long did the current flow? Calculate the mass of Zn deposited at the cathode of cell Y. 
(Molar mass: Fe=56g mol-1,Zn=65.3g mol-1,1F=96500C mol-1)

Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
Chapter: [3] Electrochemistry
[2.5]25.2.2

In the plot of molar conductivity (∧m) vs square root of concentration (c1/2) following curves are obtained for two electrolytes A and B : 

Answer the following:
(i) predict the nature of electrolytes A and B.
(ii) What happens on the extrapolation of ∧m to concentration approaching for electrolytes A and B?

Concept: Conductance of Electrolytic Solutions - Variation of Conductivity and Molar Conductivity with Concentration
Chapter: [3] Electrochemistry
[5]26
[5]26.1
[2]26.1.1
[1]26.1.1.1

How do you convert the following :
Phenol to anisole

Concept: Preparation of Ethers from Dehydration of Alcohols and Williamson Systhesis
Chapter: [11] Alcohols, Phenols and Ethers
[1]26.1.1.2

How do you convert the following : 
Ethanol to Propan-2-ol 

Concept: Some Commercially Important Alcohols
Chapter: [11] Alcohols, Phenols and Ethers
[2]26.1.2

Write the mechanism of the following reaction : 

\[\ce{C2H5OH->[H2SO4][443K]CH2=CH2 + H2O}\]

Concept: Some Commercially Important Alcohols
Chapter: [11] Alcohols, Phenols and Ethers
[1]26.1.3

Why phenol undergoes electrophilic substitution more easily than benzene? 

Concept: Chemical Reaction of Ethers - Electrophilic Substitution
Chapter: [11] Alcohols, Phenols and Ethers
OR
[5]26.2
[2]26.2.1
[1]26.2.1.1

Account for the following : 

o-nitrophenol is more steam volatile than p-nitrophenol.  

Concept: Classification of Crystalline Solids
Chapter: [1] Solid State
[1]26.2.1.2

Account for the following : 
t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butyl methyl ether.

Concept: Preparation of Ethers from Dehydration of Alcohols and Williamson Systhesis
Chapter: [11] Alcohols, Phenols and Ethers
[2]26.2.2
[1]26.2.2.1

Write the equation involved in Reimer-Tiemann reaction.

 

Concept: Chemical Reactions of Phenols (Only)
Chapter: [11] Alcohols, Phenols and Ethers
[1]26.2.2.2

Write the equation involved in Friedal-Crafts Alkylation of Phenol 

Concept: Amines - Chemical Reactions of Amines - Alkylation and Acylation
Chapter: [13] Organic Compounds Containing Nitrogen
[1]26.3

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
[5]27
[3]27.1
[1]27.1.1

Give reason for the following :  
Sulphur in vapour state shows paramagnetic behaviour. 

Concept: Magnetic Properties
Chapter: [1] Solid State
[1]27.1.2

Give a reason for the following : 
N-N bond is weaker than the P-P bond.

Concept: Carboxylic Acids - Chemical Reactions of Carboxylic Acids - Reactions Involving –COOH Group
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[1]27.1.3

Give a reason for the following :
Ozone is thermodynamically less stable than oxygen. 

Concept: P - Block Group 16 Elements - Ozone
Chapter: [7] P - Block Elements
[2]27.2
[1]27.2.1

Write the name of gas released when Cu is added to dilute HNO3

Concept: Solubility - Solubility of a Gas in a Liquid
Chapter: [2] Solutions
[1]27.2.2

Write the name of gas released when Cu is added to the conc. HNO

Concept: Solubility - Solubility of a Gas in a Liquid
Chapter: [2] Solutions
OR
[5]27.3
[2]27.3.1
[1]27.3.1.1

Answer the following question.
Write the disproportionation reaction of H3PO3

Concept: P - Block Group 15 Elements - Phosphorus - Allotropic Forms
Chapter: [7] P - Block Elements
[1]27.3.1.2

Draw the structure of XeF4

Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
Chapter: [7] P - Block Elements
[2]27.4
[1]27.4.1

Account for the following : 
Although Fluorine has less negative electron gain enthalpy yet F2 is a strong oxidizing agent.

Concept: P Block Elements
Chapter: [7] P - Block Elements
[1]27.4.2

Account for the following : 
Acidic character decreases from N2O3 to Bi2O3 in group 15.

Concept: Concept of Group 15 Elements
Chapter: [7] P - Block Elements
[1]27.5

Answer the following question.
Write a chemical reaction to test sulphur dioxide gas. write a chemical equation involved.

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

Request Question Paper

If you dont find a question paper, kindly write to us





      View All Requests

Submit Question Paper

Help us maintain new question papers on Shaalaa.com, so we can continue to help students




only jpg, png and pdf files

CBSE previous year question papers Class 12 Chemistry with solutions 2018 - 2019

     CBSE Class 12 Chemistry question paper solution is key to score more marks in final exams. Students who have used our past year paper solution have significantly improved in speed and boosted their confidence to solve any question in the examination. Our CBSE Class 12 Chemistry question paper 2019 serve as a catalyst to prepare for your Chemistry board examination.
     Previous year Question paper for CBSE Class 12 Chemistry-2019 is solved by experts. Solved question papers gives you the chance to check yourself after your mock test.
     By referring the question paper Solutions for Chemistry, you can scale your preparation level and work on your weak areas. It will also help the candidates in developing the time-management skills. Practice makes perfect, and there is no better way to practice than to attempt previous year question paper solutions of CBSE Class 12.

How CBSE Class 12 Question Paper solutions Help Students ?
• Question paper solutions for Chemistry will helps students to prepare for exam.
• Question paper with answer will boost students confidence in exam time and also give you an idea About the important questions and topics to be prepared for the board exam.
• For finding solution of question papers no need to refer so multiple sources like textbook or guides.
S
View in app×