Copy of MGS Chemistry P3 (Q3)

Page 8 of 11 Methodist Girls’ School Chemistry Paper 3 Sec 4 Preliminary Examination 2024 Class Index Number Name : __________________________________________ 3 Read all the instructions carefully before starting the experiments in Question 3. (a) You are provided with two samples of R and a sample of solution S. Carry out the following tests and record your observations in the table. You should test and name any gas evolved. Test No. Test Observations 1 Remove the stopper from a sample of R in a test -tube. Heat the solid in the test - tube gently at first and then strongly. Leave it to cool. You do not need to test for any gas evolved. 2 Transfer the other provided sample of solid R to a boiling tube. Carefully add hydrochloric acid to a depth of approximately 5 cm. Test any gases given off. Keep this solution for Test 3 and 4. 3 Add 1 cm depth of the solution from Test 2 into a test -tube. Add aqueous sodium hydroxide slowly with shaking until no further change is seen. 4 Add 1 cm depth of the solution from Test 2 into a test-tube. Add aqueous ammonia slowly with shaking until no further change is seen. 5 To 1 cm depth of S in a test -tube, add aqueous sodium hydroxide until no further change is seen. Allow the final mixture to stand for a few minutes.

Page 9 of 11 Methodist Girls’ School Chemistry Paper 3 Sec 4 Preliminary Examination 2024 6 (a) To 1 cm depth of S in a test-tube, add an equal volume of aqueous hydrogen peroxide. (b) Pour the mixture from ( a) into a boiling tube and then add aqueous sodium hydroxide. 7 (a) To 1 cm depth of S in a test-tube, add an equal volume of aqueous barium nitrate. (b) Add dilute nitric acid to the mixture from (a). 8 To 1 cm depth of acidified potassium manganate (VII) in test-tube, add an equal volume of S. [12] (b) State the formula of solid R. [1] (c) Deduce the role of S in Test 8. Use your observations to explain how you have reached this conclusion. [2] [Total: 15]

Page 10 of 11 Methodist Girls’ School Chemistry Paper 3 Sec 4 Preliminary Examination 2024

Page 11 of 11 Methodist Girls’ School Chemistry Paper 3 Sec 4 Preliminary Examination 2024 QUALITATIVE ANALYSIS NOTES Test for anions anion test test result carbonate (CO32-) add dilute acid effervescence, carbon dioxide produced chloride (Cl-) [in solution] acidify with dilute nitric acid, then add aqueous silver nitrate white ppt. iodide (I-) [in solution] acidify with dilute nitric acid, then add aqueous silver nitrate yellow ppt. nitrate (NO3-) [in solution] add aqueous sodium hydroxide, then aluminium foil; warm carefully ammonia produced sulfate (SO42-) [in solution] acidify with dilute nitric acid, then add aqueous barium nitrate white ppt. Test for aque