ISC 2015 Chemistry Question Paper for Class 12

About this paper

This is ISC Class 12 Chemistry Paper 1 (Theory) from the 2015 CISCE board examination, paper code 862A (printed as 1215-862 A). The time allowed is three hours, with fifteen minutes extra for reading. Part I is compulsory and carries 20 marks. From Part II, which carries 50 marks, candidates answer six questions: two from Section A, two from Section B and two from Section C. Section A is physical chemistry, Section B general and inorganic chemistry, and Section C organic chemistry. A table of constants is printed, including R, the Faraday and Avogadro's number, and balanced equations are required wherever possible. This copy has the questions only.

Exam

ISC Class 12

Subject

Chemistry

Year

2015

Paper code

862A

Maximum marks

70

Time allowed

3 hours + 15 min reading

Questions

10

Pages

7

Answers included

No, questions only

Paper pattern

• Part I

  20 marks

  Question 1 is compulsory: five fill-in-the-blanks, five multiple-choice items, five short answers and a five-point match

• Section A

  20 marks

  Questions 2–4 on physical chemistry, 10 marks each; answer any two

• Section B

  10 marks

  Questions 5–7 on coordination compounds, the p-block and metallurgy, 5 marks each; answer any two

• Section C

  20 marks

  Questions 8–10 on organic chemistry, 10 marks each; answer any two

Topics covered

• Electrochemistry
• Solid state
• Ionic equilibrium and solubility product
• Chemical kinetics
• Colligative properties
• Chemical equilibrium
• Coordination compounds
• p-block elements
• Metallurgy of silver
• Organic name reactions
• Polymers
• Biomolecules

Questions from this paper

1. A solution of 0.5 g of KCl in 100 g of water freezes at −0.24°C. Calculate the degree of dissociation of the salt. (Kf for water = 1.86°C; K = 39, Cl = 35.5.)
2. Chromium crystallises in a body-centred cubic lattice with an edge of 287 pm. Calculate the atomic radius and the density in g/cm³. (Atomic mass of Cr = 52.99.)
3. The equilibrium constant for N₂(g) + 3H₂(g) ⇌ 2NH₃(g) at 715 K is 6.0 × 10⁻². If [H₂] = 0.25 mol L⁻¹ and [NH₃] = 0.06 mol L⁻¹, find [N₂] at equilibrium.
4. The specific conductance of 0.01 M acetic acid at 298 K is 1.65 × 10⁻⁴ ohm⁻¹ cm⁻¹. Given λ°(H⁺) = 349.1 and λ°(CH₃COO⁻) = 40.9 ohm⁻¹ cm² mol⁻¹, find the molar conductance, the degree of dissociation and Ka.
5. State the hybridisation and the magnetic property of [Fe(CN)₆]³⁻ according to the valence bond theory.
6. An organic compound A of formula C₂H₇N reacts with nitrous acid to give B. Controlled oxidation of B gives C, which reduces Tollen's reagent to a silver mirror and D. Identify A, B, C, D and E, the sweet-smelling product of B and D.