CBSE (Science) Class 12CBSE
Share
Notifications

View all notifications

Chemistry Delhi Set 3 2017-2018 CBSE (Science) Class 12 Question Paper Solution

Login
Create free account


      Forgot password?
Chemistry
Delhi Set 3
2017-2018 March
Marks: 70

[1]1

Write the coordination number and oxidation state of Platinum in the complex [Pt(en)2Cl2].

Concept: Coordination Compounds Numerical
Chapter: [9] Coordination Compounds
[1]2

An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.

Concept: General Properties of the Transition Elements (D-block)
Chapter: [8] "D" and "F" Block Elements
[1]3

Out of chlorobenzene and benzyl chloride, which one gets easily hydrolysed by aqueous NaOH and why?

Concept: Compounds of Halogens
Chapter: [7] P - Block Elements
[1]4

Write the IUPAC name of the following :

Concept: Alcohols, Phenols and Ethers - Nomenclature
Chapter: [11] Alcohols, Phenols and Ethers
[1]5

CO (g) and H2 (g) react to give different products in the presence of different catalysts. Which ability of the catalyst is shown by these reactions?

Concept: Catalysis - Catalysts in Industry
Chapter: [5] Surface Chemistry
[2]6

Among the hydrides of Group-15 elements, which have the lowest boiling point?

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

Among the hydrides of Group-15 elements, which have the maximum basic character?

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

Among the hydrides of Group-15 elements, which have the highest bond angle?

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

Among the hydrides of Group-15 elements, which have the maximum reducing character?

Concept: Concept of Group 15 Elements
Chapter: [7] P - Block Elements
[2]7

Calculate the freezing point of a solution containing 60 g of glucose (Molar mass = 180 g mol–1) in 250 g of water. (Kf of water = 1.86 K kg mol–1)

Concept: Colligative Properties and Determination of Molar Mass - Depression of Freezing Point
Chapter: [2] Solutions
[2]8 | Attempt Any One
[2]8.1

How do you convert the Ethanal to Propanone

Concept: Alcohols, Phenols and Ethers - Nomenclature
Chapter: [11] Alcohols, Phenols and Ethers

How do you convert the Toluene to Benzoic acid

Concept: Carboxylic Acids - Nomenclature
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[2]8.2

Account for the following:

Aromatic carboxylic acids do not undergo Friedel-Crafts reaction.

Concept: Carboxylic Acids - Structure of the Carboxyl group
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids

Account for the following:

pKa value of 4-nitrobenzoic acid is lower than that of benzoic acid.

Concept: Physical Properties of Carboxylic Acids
Chapter: [12] Aldehydes, Ketones and Carboxylic Acids
[2]9

Complete and balance the following chemical equations

`Fe^(2+) + MnO_4^(-) + H^+ ->`

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

Complete and balance the following chemical equations

`MnO_4^(-) + H_2O + I^(-) ->`

Concept: General Properties of the Transition Elements (D-block)
Chapter: [8] "D" and "F" Block Elements
[2]10

For the reaction 

2N2O5 (g) → 4NO2 (g) + O2 (g), the rate of formation of NO2 (g) is 2·8 × 10–3 M s–1. Calculate the rate of disappearance of N2O5 (g).

Concept: Rate of a Chemical Reaction
Chapter: [4] Chemical Kinetics
[3]11

Identify the chiral molecule in the following pair :

 

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

Write the structure of the product when chlorobenzene is treated with methyl chloride in the presence of sodium metal and dry ether.

Concept: Compounds of Halogens
Chapter: [7] P - Block Elements

Write the structure of the alkene formed by dehydrohalogenation of 1-Bromo-1methylcyclohexane with alcoholic KOH.

Concept: Compounds of Halogens
Chapter: [7] P - Block Elements
[3]12

A first-order reaction is 50% completed in 40 minutes at 300 K and in 20 minutes at 320 K. Calculate the activation energy of the reaction. (Given : log 2 = 0·3010, log 4 = 0·6021, R = 8·314 JK–1 mol–1)

Concept: Temperature Dependence of the Rate of a Reaction
Chapter: [4] Chemical Kinetics
[3]13

An element 'X' (At. mass = 40 g mol-1) having f.c.c. the structure has unit cell edge length of 400 pm. Calculate the density of 'X' and the number of unit cells in 4 g of 'X'. (NA = 6.022 × 1023 mol-1)

Concept: Number of Atoms in a Unit Cell
Chapter: [1] Solid State
[3]14

Give reasons for the following:

Measurement of osmotic pressure method is preferred for the determination of molar masses of macromolecules such as proteins and polymers.

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

Give reasons for the following :

Aquatic animals are more comfortable in the cold water than in warm water.

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

Give reasons for the following

Elevation of the boiling point of 1 M KCl solution is nearly double than that of 1 M sugar solution.

Concept: Abnormal Molar Masses
Chapter: [2] Solutions
[3]15

What happens when a freshly prepared precipitate of Fe(OH)3 is shaken with a small amount of FeCl3 solution?

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

What happens when persistent dialysis of a colloidal solution is carried out?

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

What happens when an emulsion is centrifuged?

Concept: Properties of Colloidal Solutions
Chapter: [5] Surface Chemistry
[3]16

Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN and Zn in this process.

Concept: Concentration of Ores - Leaching
Chapter: [6] General Principles and Processes of Isolation of Elements
[3]17

(A), (B) and (C) are three non-cyclic functional isomers of a carbonyl compound with molecular formula C4H8O. Isomers (A) and (C) give positive Tollens' test whereas isomer (B) does not give Tollens' test but gives positive Iodoform test. Isomers (A) and (B) on reduction with Zn(Hg)/conc. HCl give the same product (D).

1) Write the structures of (A), (B), (C) and (D).

2) Out of (A), (B), and (C) isomers, which one is least reactive towards the addition of HCN?

Concept: Bonding in Metal Carbonyls
Chapter: [9] Coordination Compounds
[3]18

Why is bithional added to soap?

Concept: Cleansing Agents - Soaps
Chapter: [16] Chemistry in Everyday Life

What is tincture of iodine? What is its use?

Concept: Therapeutic Action of Different Classes of Drugs - Antimicrobials
Chapter: [16] Chemistry in Everyday Life

Among the following, which one acts as a food preservative?

Aspartame, Aspirin, Sodium Benzoate, Paracetamol

Concept: Chemicals in Food - Artificial Sweetening Agents and Food Preservatives
Chapter: [16] Chemistry in Everyday Life
[3]19

Write the formulas for the following coordination compounds:

Iron(III) hexacyanoferrate(II)

Concept: Introduction of Coordination Compounds
Chapter: [9] Coordination Compounds

What type of isomerism is exhibited by the complex `[Co(NH_3)_5Cl]SO_4`?

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

Write the hybridisation and number of unpaired electrons in the complex `[CoF_6]^(3-)`. (Atomic No. of Co = 27)

Concept: Bonding in Coordination Compounds - Valence Bond Theory (VBT)
Chapter: [9] Coordination Compounds
[3]20 | Attempt Any One
[3]20.1

Define the following with an example of each

Polysaccharides

Concept: Carbohydrates - Polysaccharides - Starch, Cellulose and Glycogen
Chapter: [14] Biomolecules

Define the following with an example

Denatured protein

Concept: Proteins - Denaturation of Proteins
Chapter: [14] Biomolecules

Define the following terms: Essential amino acids

Concept: Proteins - Amino Acids
Chapter: [14] Biomolecules
[3]20.2

Write the product when D-glucose reacts with conc. HNO3.

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

Amino acids show amphoteric behaviour. Why?

Concept: Proteins - Amino Acids
Chapter: [14] Biomolecules

Write one difference between α-helix and β-pleated structures of proteins.

Concept: Proteins - Structure of Proteins
Chapter: [14] Biomolecules
[3]21

Write the structures of the main products in the following reactions :

Concept: Importance and Applications of Coordination Compounds
Chapter: [9] Coordination Compounds

Write the structures of the main products in the following reactions :

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

Write the structures of the main products in the following reactions :

Concept: Chemical Reaction of Ethers - Cleavege of C-O Bonds
Chapter: [11] Alcohols, Phenols and Ethers
[3]22

Give reasons: E° value for the Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.

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

Give reasons Iron has the higher enthalpy of atomization than that of copper.

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

Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.

Concept: General Properties of the Transition Elements (D-block)
Chapter: [8] "D" and "F" Block Elements
[4]23

Shyam went to a grocery shop to purchase some food items. The shopkeeper packed all the items in polythene bags and gave them to Shyam. But Shyam refused to accept the polythene bags and asked the shopkeeper to pack the items in paper bags. He informed the shopkeeper about the heavy penalty imposed by the government for using polythene bags. The shopkeeper promised that he would use paper bags in future in place of polythene bags.

1) Write the values (at least two) shown by Shyam.

2) Write one structural difference between low-density polyethene and high-density polyethene.

3) Why did Shyam refuse to accept the items in polythene bags?

4) What is a biodegradable polymer? Give an example.

 

Concept: Polymers - Classification of Polymers Based on Mode of Polymerisation
Chapter: [15] Polymers
[5]24 | Attempt Any One
[5]24.1

Write the chemical equations involved in the following reactions:(i) Hoffmann-bromamide degradation reaction

Concept: Amines - Preparation of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Write short notes on Diazotisation

Concept: Introduction of Diazonium Salts
Chapter: [13] Organic Compounds Containing Nitrogen

Illustrate the following reaction giving suitable example in each case:Gabriel phthalimide synthesis

Concept: Amines - Preparation of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Give reason (CH3)2NH is more basic than (CH3)3N in an aqueous solution.

Concept: Physical Properties of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Give reason Aromatic diazonium salts are more stable than aliphatic diazonium salts.

Concept: Physical Properties of Diazonium Salts
Chapter: [13] Organic Compounds Containing Nitrogen
[5]24.2

Write the structures of the main products of the following reactions:

Concept: Amines - Chemical Reactions of Amines - Basic Character of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Write the structures of the main products of the following reactions:

Concept: Amines - Chemical Reactions of Amines - Basic Character of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Write the structures of the main products of the following reactions:

Concept: Amines - Chemical Reactions of Amines - Basic Character of Amines
Chapter: [13] Organic Compounds Containing Nitrogen

Give a simple chemical test to distinguish between Aniline and N, N-dimethylaniline

Concept: Amines - Chemical Reactions of Amines - Carbylamine Reaction
Chapter: [13] Organic Compounds Containing Nitrogen

Arrange the following in the increasing order of their pKvalues:

C6H5NH2, C2H5NH2, C6H5NHCH3

Concept: Amines - Preparation of Amines
Chapter: [13] Organic Compounds Containing Nitrogen
[5]25 | Attempt Any One
[5]25.1

Give reasons H3PO3 undergoes disproportionation reaction but H3PO4 does not.

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

Give reasons When Cl2 reacts with the excess of F2, ClF3 is formed and not FCl3.

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

Give reasons Dioxygen is a gas while Sulphur is a solid at room temperature.

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

Draw the structures of the following molecules: XeF4

Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
Chapter: [7] P - Block Elements

Draw the structures of the HClO3

Concept: P - Block Group 17 Elements - Oxoacids of Halogens
Chapter: [7] P - Block Elements
[5]25.2

When concentrated sulphuric acid was added to an unknown salt present in a test tube a brown gas (A) was evolved. This gas intensified when copper turnings were added to this test tube. On cooling, the gas (A) changed into a colourless solid (B).

1) Identify (A) and (B).

2) Write the structures of (A) and (B).

3) Why does gas (A) change to solid on cooling?

Concept: P - Block Group 16 Elements - Sulphuric Acid
Chapter: [7] P - Block Elements

Arrange the following in the decreasing order of their reducing character :

HF, HCl, HBr, HI

Concept: P - Block Group 17 Elements - Concept of Group 17 Elements
Chapter: [7] P - Block Elements

What happens when: XeF4 reacts with SbF5?

Concept: P - Block Group 18 Elements - Concept of Group 18 Elements
Chapter: [7] P - Block Elements
[5]26 | Attempt Any One
[5]26.1

Write the cell reaction and calculate the e.m.f of the following cell at 298 K:

`Sn(s) | Sn^(2+) (0.004 M) || H^(+) (0.020 M) | H_2 (g) ("1 bar") | Pt(s)`

(Given: `E_(Sn^(2+)"/"Sn)^0 = -0.14` V)

Concept: Galvanic Cells - Measurement of Electrode Potential
Chapter: [3] Electrochemistry

Give reasons On the basis of E° values, O2 gas should be liberated at anode but it is Cl2 gas which is liberated in the electrolysis of aqueous NaCl.

Concept: Conductance of Electrolytic Solutions - Measurement of the Conductivity of Ionic Solutions
Chapter: [3] Electrochemistry

Give reasons Conductivity of CH3COOH decreases on dilution.

Concept: Conductance of Electrolytic Solutions - Measurement of the Conductivity of Ionic Solutions
Chapter: [3] Electrochemistry
[5]26.2

For the reaction

`2AgCl (s) + H_2 (g) ("1 atm") -> 2Ag (s) + 2H^(+)  (0.1 M) +  2Cl^(-) (0.1 M)`

`triangleG^0 = -43600 J at 25^@ C`

Calculate the e.m.f. of the cell

`[log 10^(-n) = -n]` 

Concept: Relation Between Gibbs Energy Change and Emf of a Cell
Chapter: [3] Electrochemistry

Define terms: Fuel cell

Concept: Batteries - Primary Batteries
Chapter: [3] Electrochemistry

Write two advantages of fuel cell

Concept: Fuel Cells
Chapter: [3] Electrochemistry

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 2017 - 2018

     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 2018 serve as a catalyst to prepare for your Chemistry board examination.
     Previous year Question paper for CBSE Class 12 Chemistry-2018 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×