RVHS_2023_J2_H2_CM_Prelim_P3_QP

River Valley High School 9729/03/PRELIMS/23 2023 Preliminary Examination [Turn over RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 2 J CENTRE NUMBER S INDEX NUMBER H2 CHEMISTRY 9729/03 Paper 3 Free Response 20 September 2023 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your Centre number, index number, class and name on all the work that you hand in. 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. DO NOT WRITE IN ANY BARCODES. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. Section A Answer all the questions. Section B Answer one question. Circle the question number of the question you attempted. 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 Question Number 1 2 3 4 5 units s.f. Total Marks 19 24 17 20 20 80 This document consists of 28 printed pages.

2 River Valley High School 9729/03/PRELIMS/23 2023 Preliminary Examination Section A Answer all the questions in this section. 1 (a) Ethanedioyl dibromide, BrCOCOBr, is a useful reagent in organic synthesis. ethanedioyl dibromide Ethanedioyl dibromide is used in the following synthesis of compound D. It reacted in a 1:1 stoichiometric ratio with C6H5Br in step 3. (i) Suggest the identities of A, B and C. [3] (ii) State the reagents and conditions for steps 2, 4 and 6. [3] (iii) If the amount of ethanedioyl dibromide used in step 3 is decreased, another compound is formed . The compound has the molecular formula C14H8O2Br2. Suggest the structure of this compound. [1]

3 River Valley High School 9729/03/PRELIMS/23 2023 Preliminary Examination [Turn over (iv) A student has 3 unlabelled bottles, each containing a chemical found in the above synthesis pathway. These chemicals are as shown: C6H5Br Suggest 2 simple chemical tests that will allow the student to identify the chemical in each bottle, stating clearly the observations in each test. [4] ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......… ………………………………………………………………………………......…