TJC 2026 H2 Chemistry Prelims Paper 4 QP

9476 / TJC Prelim / 2026 [Turn Over TEMASEK JUNIOR COLLEGE 2026 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS CENTRE NUMBER S INDEX NUMBER Chemistry 9476/04 Paper 4 Practical 27 August 2026 2 hours 30 minutes Candidates answer on the Question Paper. READ THESE INSTRUCTIONS FIRST Write your name, CG, centre number and index number on all the work you hand in. Give details of the practical shift and laboratory where appropriate, in the boxes provided. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Qualitative Analysis Notes are printed on pages 18 to 20. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 20 printed pages. For Examiner’s Use 1 2 3 4 Total Shift Laboratory

2 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 Answer all the questions in the spaces provided. 1 Qualitative analysis At each stage of any test you are to record details of the following: • colour changes seen • the formation of any precipitate • the solubility of such precipitates in an excess of the reagent added. Test and identify any gases evolved. You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted. Rinse and reuse test-tubes and boiling tubes where possible. (a) FA 1 is a mixture of two salts, each of which contains a single cation and a single anion from those listed in the Qualitative Analysis Notes on pages 18 to 20. Do the following tests and record your observations in Table 1.1 below. Table 1.1 test observations (i) Place a small spatula of FA 1 in a test-tube. Carefully add dilute sulfuric acid until the reaction is complete. Then add aqueous sodium hydroxide with shaking, until the aqueous sodium hydroxide is in excess. (ii) To a 3 cm depth of deionised water in a boiling tube, add the remaining sample of FA 1. Stir and then filter the mixture into a clean boiling tube. You will use this solution for tests (iii) – (v).

3 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 [Turn over (iii) Add 1 cm depth of the solution from (ii) into a clean test-tube. Add aqueous sodium hydroxide slowly, until the aqueous sodium hydroxide is in excess. (iv) Add 1 cm depth of the solution from (ii) into a clean test-tube. Add aqueous ammonia slowly, until the aqueous ammonia is in excess. Then add a spatula full of ammonium chloride. (v) Add 1 cm depth of the solution from (ii) into a clean test-tube. Add 1 cm depth of aqueous barium nitrate. Add dilute nitric acid until the nitric acid is in excess. [4] (vi) Complete Table 1.2 to identify the cations and anions present in FA 1. Table 1.2 FA 1 cations present anions present [2] (vii) With the aid of an equation, explain your observation in part (a)(i) that allows you to identify one of the cations.

4 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………...……………………………[1] (viii) Give one reason why it is necessary to perform (a)(ii) before (a)(iii) and (a)(iv). ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………...……………………………[1] (b) Organic analysis FA 2, FA 3 and FA 4 are aqueous solutions of organic compounds. All FA 2, FA 3 and FA 4 contain carbon, hydrogen and oxygen only and they each contain one type of functional group. You will carry out tests to identify the functional group s present in FA 2, FA 3 and FA 4 and to deduce the structures of FA 2 and FA 4. (i) Perform the tests described in Table 1.3. Some of the observations have been completed for you. There is no need to carry out these tests. R ecord your observations in Table 1.3. Test and identify any gases evolved. If there is no observable change, write no observable change. When organic solutions are to be heated, a hot water bath should be used.

5 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 [Turn over Table 1.3 test observations FA 2 FA 3 FA 4 1 Add 1 cm depth of the FA solution in a test - tube. Add a small spatula of sodium carbonate to the test-tube. 2 Add 1 cm depth of the FA solution in a test - tube. Add 5 cm depth of 2,4- dinitrophenylhydrazine solution to the test - tube. no observable change no observable change orange precipitate observed 3 Add a few drops of the FA solution in a test - tube. Add a spatula of PC l5 to the test-tube. white fumes observed white fumes observed no observable change 4 Add 1 cm depth of the FA solution in a test - tube. Add 15 drops of dilute sulfuric acid followed by 1 drop of acidified potassium manganate(VII). Place the test -tube in the hot water bath and leave to stand. [2] (ii) Using your observations from Table 1.3, deduce the functional group present in both FA 2 and FA 3. ……………………………………………………………………………………………… ……………………………………………………………...……………………………[1]

6 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 (iii) Hence, suggest a possible structure of FA 2 that is consistent with all the observations in Table 1.3. [1] (iv) The relative molecular mass of FA 4 is determined to be 58.0. Using your observations from Table 1.3, suggest the structure of FA 4. Give evidence to support your conclusion. [Ar: H, 1.0; C, 12.0; O, 16.0] ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………...……………………………[1] [Total: 13]

7 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9476 / TJC Prelim / 2026 [Turn over 2 Investigate the kinetics of the reaction between M3+ ions and iodide ions FA 5 is 0.0500 mol dm−3 aqueous potassium iodide, KI. FA 6 is an acidified solution of M3+(aq). FA 7 is 0.00500 mol dm−3 sodium thiosulfate, Na2S2O3. You are also provided with: • starch solution • deionised water In acidic solutions, M3+ ions react with iodide ions according to the equation shown. 2M3+(aq) + 2I−(aq) → 2M2+(aq) + I2(aq) In this experiment, the rate of the reaction can be investigated by using starch indicator, which turns blue-black in the presence of iodine. Sodium thiosulfate is added to the reaction mixture to react with iodine as it is formed. When all the thiosulfate has reacted, the black -blue colour is observed. I2(aq) + 2S2O32–(aq) → 2I–(aq) + S4O62–(aq) You will perform a series of five experiments to investigate how the rate of reaction is affected by changing the concentration of the iodide ions. You will measure the time, t, for the blue-black colour to appear. For each experiment, you will need to ensure that the total volume of reac