HCI 2021 Prelim Paper 2 Questions

This document consists of 18 printed pages. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 20S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 9729/02 25 August 2021 2 hours READ THESE INSTRUCTIONS FIRST Write your name, Centre number, index number and CT group clearly in the spaces at the top of the page. Write in dark blue or black pen. You may use a 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. For Examiner’s Use 1 / 16 2 / 18 3 / 16 4 / 25 Deductions s.f. units Total / 75

2 © Hwa Chong Institution 2021 9729/02/C2Prelim 2021 [Turn over Answer all the questions in the spaces provided. 1 Hypoglycin A occurs naturally in fruits such as lychees and longans. In 2017, scientists advised against over-consuming lychees on an empty stomach after discovering its role in a mysterious recurring outbreak of acute neurological illness since 1995 in Bihar, the largest lychee cultivation area in India. hypoglycin A, C7H11O2N For Examiner's use (a) (i) Hypoglycin A contains a carboxylic acid functional group. Explain the acidity of the carboxylic acid functional group in terms of its structure. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (ii) Identify as fully as you can the other functional groups present in hypoglycin A. ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (iii) Explain whether hypoglycin A can show cis-trans isomerism. ……………………………………………………………………………………………… ……………………………………………………………………………………………[1]

3 © Hwa Chong Institution 2021 9729/02/C2Prelim 2021 [Turn over (b) Draw the structures of the major organic products, P, Q and R, when hypoglycin A reacts with each of the following reagents. For Examiner's use [3] (c) Hypoglycin A can be synthesised from a 3-stage process. (i) In the journal article where this synthesis was first published, stage I was described as a “condensation” reaction. Identify the small molecule that was produced. ……………………………………………………………………………………………[1] (ii) Suggest the type of reaction that occurs in stage II. ……………………………………………………………………………………………[1] (iii) In stage III, one of the two –CO2C2H5 groups in the intermediate compound is lo