ISC 2016 Chemistry Practical Question Paper for Class 12

About this paper

This is ISC Class 12 Chemistry Paper 2 (Practical), code 862B, from the 2016 board examination. It carries 30 marks over three hours, with fifteen minutes extra for reading, and all four questions are compulsory. Question 1 is a redox titration of potassium manganate(VII), 1.60 g per litre, against hydrated ammonium iron(II) sulphate, 20.3 g per litre, and asks for the water of crystallisation. Question 2 studies how the concentration of 0.2 M sodium thiosulphate changes the rate of its reaction with 0.1 M hydrochloric acid, timed by the disappearance of a cross and plotted on the graph paper supplied. Question 3 is qualitative analysis of a salt with two anions and two cations. Question 4 is the project and the practical file. This copy has the questions only.

Exam

ISC Class 12

Subject

Chemistry Practical

Year

2016

Paper code

862B

Maximum marks

30

Time allowed

3 hours + 15 min reading

Questions

4

Pages

4

Answers included

No, questions only

Paper pattern

• Question 1

  8 marks

  Redox titration of potassium manganate(VII) against hydrated ammonium iron(II) sulphate, including the value of x

• Question 2

  5 marks

  Effect of sodium thiosulphate concentration on the rate of its reaction with hydrochloric acid, with a graph

• Question 3

  7 marks

  Qualitative analysis of substance C-15, which contains two anions and two cations

• Question 4

  10 marks

  Project (7 marks) and chemistry practical file (3 marks)

Topics covered

• Redox titration
• Potassium permanganate
• Mohr's salt
• Rate of reaction
• Sodium thiosulphate and hydrochloric acid
• Qualitative analysis of anions
• Qualitative analysis of cations

Questions from this paper

1. C-10 contains 1.60 g of potassium manganate(VII) per litre and C-11 contains 20.3 g of hydrated ammonium iron(II) sulphate, (NH4)2SO4·FeSO4·xH2O, per litre. Find both molarities, the molecular mass of the iron salt and the value of x.
2. Using 0.2 M sodium thiosulphate and 0.1 M hydrochloric acid, time how long a cross marked on paper takes to disappear as the thiosulphate is diluted, and plot that volume against time.
3. From the graph, find the time taken for the reaction when 25 ml of the sodium thiosulphate solution is used, and state how concentration affects the rate.
4. Analyse substance C-15 qualitatively. It contains two anions and two cations, and a qualitative analysis booklet or table may not be used.