CJC 2026 Prelim P3 QP

9476/03 CJC JC2 Preliminary Examination 2026 [Turn over CANDIDATE NAME CLASS 2T INDEX NUMBER CHEMISTRY 9476/03 Paper 3 Structured Questions 14 September 2026 2 hours You must answer on the question paper. You will need: Data booklet INSTRUCTIONS • Answer all questions. • Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. • Write your name, class and index number in the boxes at the top of the page. • Write your answer to each question in the space provided. • Do not use an erasable pen. Do not use correction fluid or tape. • You may use an approved calculator. INFORMATION • The total mark for this paper is 75. • The number of marks for each question paper or part question is shown in brackets [ ]. This document has 22 pages. Any blank pages are indicated. For Examiner’s Use Section A Q1 /18 Q2 /18 Q3 /19 Section B Q4 /20 OR Q5 /20 TOTAL 75 Catholic Junior College JC2 Preliminary Examination Higher 2

2 9476/03 CJC JC2 Preliminary Examination 2026 Section A Answer all the questions in this section in the spaces provided. 1 (a) State how the reactivity of the halogens (from chlorine to iodine) as oxidising agents varies down the group and relate this variation to relevant Eo values from the Data Booklet. ……………………………………………………….……..………………………………………………. ……………………………………………………….……..………………………………………………. ……………………….……………………………………………………….……..……………………… …………………………………..…..……………………………………………………………………… .…………………...…….…………………..……………………………………………………...………. .………………………………………………………………………………………..……………………. ….………………………..…………………………………………………………………………………. ………..………………………………………………………………………………………..…………… …………………………………………………………………………….……..……...……………… [3] (b) Write an equation that illustrates the relative oxidising abilities of chlorine and bromine, and state the expected observations. …..…………………………………………………………………………………………...….…….…… ………..…………………………………………………………………………………………………..… ……………………………………………………………………………………………………………… ……..………………………………………………………………………………………………….…[2] (c) Ethylamine, diethylamine and triethylamine can act as Lewis bases in the gaseous phase. Describe and explain their relative basicities. ………………………………………………………………………………...……..…………………… ………………………………………………………………………………...……..…………………… ………………………………………………………………………………...……..…………………… ……………………………………………………………………...……..……………………………… …………………………………………………………...……..………………………………………… ………………………………………………...……..…………………………………………………… ……………………………………...……..……………………………………………………………… …………………………...……..………………………………………………………………………… ………………...…………………………………………………………………………………………[3]

3 9476/03/CJC JC2 Preliminary Examination 2026 [Turn over (d) Explain why amides, RCONH2, are neutral, rather than basic in aqueous solution. …………………..………………………………………………………………………………..………… ……………………………………..……………………………………………………………………..… ….………..………………………………………………………………………………………………[1] (e) Imidazole is an organic compound that is very well studied due to many natural occurring compounds, such as caffeine and histidine, containing the imidazole ring. Imidazole has six  electrons and the molecule has a planar and cyclic structure, like benzene, resulting in a ring of delocalised electrons. Two representations of imidazole are shown below. In imidazole, nitrogen atoms undergo the same hybridisation as carbon atoms. State the hybridisation of nitrogen and carbon atoms and hence suggest how the  and  bonds are formed between nitrogen and carbon atoms in an imidazole molecule with reference to orbital overlap. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..………………………………………………………………………………………………………….. …..……………………………………………………………………………………………………….[3]

4 9476/03 CJC JC2 Preliminary Examination 2026 (f) Imidazole is highly soluble in water. Complete the following diagram with two water molecules to show the significant force of attraction between the water molecules and imidazole. Include the name of the attraction in your diagram. [3] . (g) Kevlar is a polymer which is used in stab-proof vests and high quality bicycle tyres. A repeat unit of Kevlar is as shown. (i) Define the term polymer. …………………………………………………………………………………………….………. …………………………………………….…………………………………………………….[1] (ii) State the type of polymerisation that occurred to form Kevlar. …………………………………………………………………………………………………[1] (iii) Kevlar is synthesised in solution from the monomers A and B. Monomer A has the following structure. Draw the structure of the monomer B used to make Kevlar. [1] [Total: 18]

5 9476/03/CJC JC2 Preliminary Examination 2026 [Turn over 2 Sulfa drugs are a class of sulfur containing compounds. They were the "wonder drugs" before penicillin was discovered. A precursor to synthesi sing such sulfa drugs is aryl sulfonic acid with the general structure shown below. Aryl sulf onic acids may be synthesi sed from the electrophilic substitution reaction between concentrated sulfuric acid and an aromatic compound. (a) In an experiment to investigate the rate of reaction between concentrated sulfuric acid and benzene to form sulfonic acid, different volumes of sulfuric acid and benzene were used and the time taken to form x mol of product were recorded in Table 1.1. Table 1.1 No. Volume of concentrated sulfuric acid / cm3 Volume of benzene / cm3 Volume of water / cm3 Time taken to form x mol of product / min 1 10 20 30 60 2 20 20 20 15 3 20 30 10 10 (i) Use the data above to deduce the order of reaction with respect to concentrated sulfuric acid and benzene, showing how you arrive at your answer. …..…………………………………………………………………………………………………….. .……..…..…………………………………………………………………………………………….. .……………..…..…………………………………………………………………………………….. .………………………………………………………………………………………………………... …..…………………………………………………………………………………………………….. .……..…..…………………………………………………………………………………………….. .………………………………………………………………………………………………………... .……………..…..…………………………………………………………………………………….. .………………………………………………………………………………………………………... .……………..…..…………………………………………………………………………………….. .……………………………………………………………………………………………….…….[4] (ii) Hence, construct the rate equation for the reaction. .……………..…..…………………………………………………………………………………….. .……………………………………………………………………………………………………...[1]

6 9476/03 CJC JC2 Preliminary Examination 2026 (b) The overall equation for the formation of the aryl sulfonic acid, C 6H5SO3H, through electrophilic substitution is given below. This reaction proceeds via a four–step mechanism. Step 1: The SO3 electrophile is first generated from concentrated sulfuric acid as given by the following equation 2H2SO4 ⇌ SO3 + H3O+ + HSO4− Step 2: The SO3 electrophile is then attacked by benzene to form an intermediate as shown below Step 3: When the intermediate from Step 2 is deprotonated, an anion as shown below is formed and sulfuric acid is regenerated Step 4: The C6H5SO3– anion is then protonated by a hydronium ion, H3O+, to form the products, C6H5SO3H and water (i) Identify which step corresponds to the rate determining step of the mechanism. .……………..…..…………………………………………………………………………………….. .……………………………………………………………………………………………………...[1]

7 9476/03/CJC JC2 Preliminary Examination 2026 [T