YIJC 2025 Prelim P2 (for exchange)_H2 Chem

©YIJC 9729/02/JC2/PE/2025 [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CG INDEX NO CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 9729/02 1 September 2025 2 hours READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this page. 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. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 21 printed pages and 3 blank pages. For Examiner’s Use 1 / 18 2 / 24 3 / 17 4 / 16 Penalty units significant figures Overall / 75

©YIJC 9729/02/JC2/PE/2025 2 Answer all the questions in the spaces provided. 1 (a) Compounds A, B and C are shown in order of increasing basicity. Explain this order. [3] (b) Amides can be found in many drugs such as paracetamol and procainamide. Procainamide can be used for the treatment of cardiac arrhythmias. procainamide Predict the products obtained when procainamide undergoes reaction with hot, dilute H2SO4. [2]

3 ©YIJC 9729/02/JC2/PE/2025 [Turn over (c) Compound J can be synthesised by the following route in Fig. 1.1, with all the carbon atoms coming from compound E. Fig. 1.1 • Compound E does not react with NaOH(aq) but reacts with Na to give a gas that extinguishes a lighted splint with a ‘pop’ sound. • Compound H is soluble in dilute HCl and can also be obtained from the reaction of compound K with LiAlH4. K • Compound J is neutral and is a cyclic molecule. (i) Draw the structure of compounds E to H, and J. E F G H J [5] (ii) State the reagents and conditions for steps 2 and 4. step 2 step 4 [2]

©YIJC 9729/02/JC2/PE/2025 4 (d) The compounds responsible for the umami flavour of soy sauce are salts of glutamic acid. glutamic acid Glutamic acid has pKa values of 2.1, 4.1 and 9.5. Draw the structure of the zwitterion. Suggest a pH at which the predominant species of glutamic acid is a zwitterion. [2] (e) A polypeptide contains 9 amino acid residues. It was partially hydrolysed to give a mixture of tripeptides. asp-gly-tyr glu-tyr-lys gly-glu-tyr met-asp-gly tyr-ala-gly Determine the sequence of amino acids that make up the