ISC 2020 Chemistry Question Paper for Class 12

About this paper

This is ISC Class 12 Chemistry Paper 1 (Theory) from the 2020 board examination, and this copy prints an answer after every question. It carries 70 marks over three hours, with fifteen minutes extra for reading, and all 18 questions are compulsory. Question 1 is worth 20 marks, questions 2 to 8 carry two marks, questions 9 to 15 carry three marks and questions 16 to 18 carry five marks. Internal choice is given in two two-mark questions, two three-mark questions and each five-mark question. The questions cover unit cells, conductivity, kinetics, coordination compounds, extraction of silver from argentite, colloids and organic name reactions. A short table of constants is printed for the numerical problems.

Exam

ISC Class 12

Subject

Chemistry

Year

2020

Maximum marks

70

Time allowed

3 hours + 15 min reading

Questions

18

Pages

7

Answers included

Yes

Paper pattern

• Question 1

  20 marks

  Four compulsory parts: fill in the blanks, multiple choice, matching and short answers

• Questions 2–8

  14 marks

  Two marks each; internal choice in two questions

• Questions 9–15

  21 marks

  Three marks each; internal choice in two questions

• Questions 16–18

  15 marks

  Five marks each, each with an internal choice

Topics covered

• Solid state
• Electrochemistry
• Chemical kinetics
• Solutions and colligative properties
• Coordination compounds
• p-block elements
• Metallurgy of silver
• Surface chemistry
• d-block elements
• Organic name reactions
• Biomolecules
• Polymers

Questions from this paper

1. An element has atomic weight 93 g mol−1 and density 11.5 g cm−3. If the edge length of its unit cell is 300 pm, identify the type of unit cell. (NA = 6.023 × 10²³ mol−1.)
2. An alloy of gold and cadmium crystallises in a cubic structure with gold atoms at the corners and cadmium atoms at the face centres. What is the formula of the alloy?
3. Draw the structure of xenon tetrafluoride, and state the hybridisation of the central atom and the geometry of the molecule.
4. How do antiseptics differ from disinfectants? Name a substance that can be used as both.
5. A first-order reaction is 50% complete in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate the activation energy. (R = 8.314 J K−1 mol−1.)
6. Name an important ore of silver and give balanced equations for the extraction of silver from its sulphide ore.