TMJC 2026 H2 Chemistry Prelim Paper 4 Answer

1 Tampines Meridian Junior College 2026 JC2 Preliminary Examination H2 Chemistry CANDIDATE NAME MARKS SCHEME CIVICS GROUP H2 CHEMISTRY 9476/04 Paper 4 Practical 2 Sep 2026 2 hour 30 minute Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. This document consists of 20 printed pages and 2 blank pages. READ THESE INSTRUCTIONS FIRST Write your name and Civics Group in the spaces at the top of the page. 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 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 19 - 21. The number of marks is given in brackets [ ] at the end of each question or part question. Shift Laboratory For Examiner’s Use 1 / 11 2 / 16 3 / 13 4 / 10 Total / 50 TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2026 JC2 Preliminary Examination H2 Chemistry Answer all the questions in the spaces provided. 1 Investigation of some inorganic and organic reactions In this question, you will be investigating some inorganic and organic reactions by carrying out the stipulated tests. Carefully record your observations in Tables 1.1 and 1.2. Unless otherwise stated, the volumes given below are approximate and should be estimated rather than measured. (a) Organic analysis In this question, you will deduce the structure of an organic compound, FA 1. FA 1 has the molecular formula C4H8O2 with two functional groups present. Do not carry out the tests for which observations have been recorded. Do not use the Bunsen burner for heating in this part of the question. Instead, use the hot water provided. Table 1.1 tests observations (i) Place about 2 cm depth of aqueous sulfuric acid in a test-tube. To this test-tube, add about 1 cm depth of FA 1, followed by 1 drop of aqueous potassium manganate(VII). Warm the mixture in the hot water bath for two minutes. • Purple KMnO4 decolourises. ✓ (ii) Place about 1 cm depth of FA 1 in a test -tube. To this test -tube, add 2,4 –dinitrophenylhydrazine dropwise. Orange ppt. formed (iii) Add 1 cm depth of aqueous silver nitrate to a test-tube. Then slowly add 1 cm depth of aqueous sodium hydroxide. Add aqueous ammonia slowly, with shaking, until the precipitate just dissolves. To this mixture, add about 1 cm depth of FA 1 . Place the test -tube containing the mixture in the hot water bath for two minutes. • Brown / grey ppt formed ✓ • Brown / grey ppt dissolves to give a colourless solution. ✓ • Silver mirror observed. ✓ Hot acidified KMnO4 ➔ Test for functional group that can be oxidised (e.g. alkenes, primary / secondary alcohols, aldehyde etc.) Type of Reaction: Oxidation 2,4-DNPH ➔ Test for aldehyde / ketone functional group Type of Reaction: Condensation Preparation of Tollens’ Reagent Tollens’ Reagent ➔ Test for aldehyde functional group Type of Reaction: Oxidation

3 Tampines Meridian Junior College 2026 JC2 Preliminary Examination H2 Chemistry [Turn over tests observations (iv) Place about 1 cm depth of FA 1 and add 8 drops of aqueous sodium hydroxide in a test -tube. Now , add iodine solution dropwise, until a permanent yellow / orange colour is obtained. Warm the mixture in the hot water bath for two minutes. • Pale yellow ppt (in yellow / orange solution) observed. ✓ (v) Place 1 cm depth of FA 1 in a test-tube. To this test-tube, cautiously add a small piece of anhydrous phosphorus pentachloride. Dense white fumes, which turns moist blue litmus paper red. [2] (b) FA 1 has the molecular formula C4H8O2 with two functional groups present. (i) Observations from (a)(ii) together with (a)(iii), can be used to identify one of the functional groups present in FA 1. Identify the functional group and explain your answer, showing clearly your reasoning. Functional group: aldehyde Explanation: [1] (ii) Observations from either (a)(iv) or (a)(v), can be used to identify the other functional group present in FA 1. Identify the functional group and explain your answer, showing clearly your reasoning. Functional group: alcohol must name, cannot only draw structure Explanation: [1] Since FA 1 undergoes condensation with 2,4 -DNPH in (a)(ii), FA 1 contains either a ketone or aldehyde . However, since FA 1 undergoes oxidation with Tollens’ reagent in (a)(iii), it contains an aldehyde. [M3] for correct type of reaction correlating to the correct deduction of functional group present Since FA 1 undergoes nucleophilic substitution with PCl5 in (a)(v) to give HCl, it contains an alcohol functional group. OR Since FA 1 undergoes oxidation with alkaline I2 in (a)( iv), it contains an alcohol functional group. [M4] for correct type of reaction correlating to the correct deduction of functional group present 4 to 5 marking points – [M1] and [M2] 2 to 3 marking points – [M1] only Anhydrous PCl5 ➔ Test for alcohol and carboxylic acid Type of Reaction: Nucleophilic Substitution OR Nucleophilic Acyl Substitution Iodoform Test ➔ Test for CH3CH(OH)- and CH3CO- Type of Reaction: Oxidation

4 Tampines Meridian Junior College 2026 JC2 Preliminary Examination H2 Chemistry (iii) Suggest a possible structure of FA 1 that is consistent with all the observations in Table 1.1. [M5] for correct structure [1] M1 M2 M3 M4 M5 • Molecular Formula: C4H8O2 • Contains aldehyde & alcohol functional group • Contains CH3 C O AND / OR CH3 C OH H

5 Tampines Meridian Junior College 2026 JC2 Preliminary Examination H2 Chemistry [Turn over (c) Inorganic analysis FA 2 contains two cations and one anion listed in the Qualitative Analysis Notes on pages 19 – 20. You should indicate clearly at what stage in a test a change occurs. Test and identify any gases evolved. If there is no observable change, write no observable change. 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 No additional tests should be attempted. Table 1.2 tests observations (i) Test the FA 2 solution using Universal Indicator paper. • Universal indicator paper turns orange-red / orange / pale orange. ✓ • pH 2 – 4✓ (ii) Add 2 cm depth of FA 2 into a test- tube. Add aqueous sodium hydroxide, slowly with shaking, until no further change is seen. Filter the mixture into a clean test-tube. To 1 cm depth of t he filtrate, add dilute nitric acid dropwise until in excess. • White Al(OH)3 (s) ppt / Off-white Mn(OH)2 (s) ppt formed, insoluble in excess NaOH (aq). ✓ • Off-white ppt turned brown on contact with air Mn(OH)3 (s). ✓ • Off-white Mn(OH)2 (s) / brown Mn(OH)3 (s) residue ✓ • Colourless filtrate Al(OH)4– (aq) ✓ • White ppt formed Al(OH)3 (s) ✓ • ppt soluble in excess HNO3 (aq) to give a colourless solution. Al3+ (aq) ✓ (iii) Add 2 cm depth of FA 2 into a test- tube. Add aqueous ammonia, slowly with shaking, until no further change is seen. Filter the mixture into a clean test-tube. To 1 cm depth of t he filtrate, add dilute nitric acid dropwise until in excess. • White Al(OH)3 (s) ppt /