JAC Class 12 Chemistry Question Paper 2020 with Solution

About this paper

This is the Jharkhand Academic Council (JAC) Class 12 Chemistry paper from the 2020 board examination. It is printed for 70 marks and three hours, with a pass mark of 23, and an answer is written under each question. All 34 questions are compulsory: eight one-mark multiple-choice items, seven one-mark very short answers, eight two-mark and eight three-mark short answers, and three five-mark long answers. The numerical long answer is the ethylene-glycol antifreeze calculation, 222.6 g dissolved in 200 g of water with density 1.072 g mL⁻¹, and its alternative is a first-order rate constant from concentrations that halve every 10 hours. The other long answers cover laboratory preparation of sulphur dioxide and the Clemmensen, Wurtz and Hell–Volhard–Zelinsky reactions.

Exam

JAC Class 12

Subject

Chemistry

Year

2020

Maximum marks

70

Time allowed

3 hours

Questions

34

Pages

4

Answers included

Yes

Paper pattern

• Multiple Choice Type Questions

  8 marks

  Questions 1–8, one mark each

• Very Short Answer Type Questions

  7 marks

  Questions 9–15, one mark each

• Short Answer Type-I

  16 marks

  Questions 16–23, two marks each

• Short Answer Type-II

  24 marks

  Questions 24–31, three marks each

• Long Answer Type

  15 marks

  Questions 32–34, five marks each, each with an Or alternative

Topics covered

• Solid state
• Solutions
• Electrochemistry
• Chemical kinetics
• Surface chemistry
• General principles of isolation of metals
• p-Block elements
• d- and f-block elements
• Coordination compounds
• Haloalkanes, alcohols and carbonyl compounds
• Biomolecules and polymers
• Chemistry in everyday life

Questions from this paper

1. What is the role of silica in the metallurgy of copper?
2. What is a salt bridge? Mention its functions.
3. Silver crystallises in a face-centred cubic lattice. The edge of the unit cell is 4.077×10⁻⁸ cm. Calculate the atomic radius and the density of silver.
4. A reaction is of second order with respect to a reactant. How is the rate affected if the concentration of that reactant is doubled?
5. An antifreeze solution is prepared from 222.6 g of ethylene glycol, C₂H₆O₂, and 200 g of water. Calculate the molality. If the density is 1.072 g mL⁻¹, what is the molarity?
6. Write short notes on the Clemmensen reduction, the Wurtz reaction and the Hell–Volhard–Zelinsky reaction.