ISC 2017 Chemistry Practical Question Paper for Class 12

About this paper

This is ISC Class 12 Chemistry Paper 2 (Practical), code 862 B, from the 2017 examination. It carries 30 marks and runs for three hours plus fifteen minutes of reading time. All four questions are compulsory. Question 1 is a redox titration: C-10 contains 3.2 g of KMnO₄ per litre, and C-11 is 6.85 g per litre of impure oxalic acid, H₂C₂O₄·2H₂O. The candidate calculates both molarities, the strength of the oxalic acid and its percentage purity. Question 2 identifies two organic compounds, and Question 3 is the qualitative analysis of a salt with two anions and two cations. A qualitative analysis table is not allowed. Question 4 is the project and the Chemistry practical file, shown to the Visiting Examiner. This copy has the questions only.

Exam

ISC Class 12

Subject

Chemistry Practical

Year

2017

Paper code

862 B

Maximum marks

30

Time allowed

3 hours + 15 min reading

Questions

4

Pages

4

Answers included

No, questions only

Paper pattern

• Question 1

  7 marks

  Redox titration of impure oxalic acid with potassium manganate(VII), with molarity, strength and percentage purity to be calculated

• Question 2

  4 marks

  Identification of two organic compounds, C-13 and C-14, from the tests given

• Question 3

  4 marks

  Qualitative analysis of C-15, which contains two anions and two cations; a qualitative analysis booklet or table is not allowed

• Question 4

  15 marks

  Project (10 marks) and Chemistry practical file (5 marks), shown to the Visiting Examiner

Topics covered

• Redox titration
• Potassium permanganate
• Oxalic acid
• Percentage purity
• Identification of organic compounds
• Qualitative analysis of anions and cations
• Project and practical file

Questions from this paper

1. C-10 contains 3.2 g of potassium manganate(VII) per litre, and C-11 is prepared by dissolving 6.85 g of impure oxalic acid crystals (H₂C₂O₄·2H₂O) per litre. Calculate the molarity of each solution, the strength of the oxalic acid in grams per litre, and the percentage purity of the sample. Give molarity to at least four decimal places.
2. Pipette out 20 ml or 25 ml of oxalic acid solution C-11, add 20 ml of dilute sulphuric acid, warm the flask to 60°C–70°C until the first bubble appears, and titrate with KMnO₄ to a permanent pale pink colour.
3. For organic compound C-13, warm a few drops with saturated sodium bisulphite, test it with freshly prepared sodium nitroprusside and dilute sodium hydroxide, and carry out the test with iodine and sodium hydroxide.
4. Dissolve 2 g of organic compound C-14 in 10 ml of hot water. Test portions with sodium bicarbonate, with concentrated sulphuric acid and ethanol on a water bath, and with neutral ferric chloride.
5. Analyse substance C-15, which contains two anions and two cations. State how the soda extract and the original solution were prepared, and give a confirmatory test for each ion. A qualitative analysis booklet or table is not allowed.