OCR A Jun 2012 Paper 2 Q6

Answers available below

6 A student carries out an investigation on some halogenoalkanes. 18 (a) She decided to hydrolyse 1-bromopentane and 1-chloropentane using aqueous sodium hydroxide. State and explain the difference in the rates of hydrolysis of 1-bromopentane and 1-chloropentane.[2] (b) A student wants to determine the structure of an unknown iodoalkane B. She knows that the molecular formula of B is C4H9I. The student heats B with aqueous sodium hydroxide. A reaction mixture forms containing the organic compound C and I(aq). (i) Draw all of the possible structural isomers for B. [4] (ii) What is the molecular formula for compound C?[1] (iii) The student purifies compound C and splits it into two portions. She heats one portion of C with concentrated sulfuric acid. The product of this reaction is methylpropene. To the other portion of C, she adds acidified potassium dichromate(VI) and heats the mixture under reflux. The product of this reaction is compound D. The infrared spectrum for compound D is shown at the top of page 19.OCR 2012<br /> 100 19 transmittance (%) 50 0 4000 3000 2000 wavenumber / cm1 1500 1000 500 Use this evidence to suggest structures for B, C and D. In your answer you should make clear how your explanations are linked to the evidence.OCR 2012 Turn over<br /> 20[6] [Total: 13] END OF QUESTION PAPER Copyright Information OCR is committed to seeking permission to reproduce all third-party content that it uses in its assessment materials. OCR has attempted to identify and contact all copyright holders whose work is used in this paper. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced in the OCR Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download from our public website (www.ocr.org.uk) after the live examination series. If OCR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OCR will be happy to correct its mistake at the earliest possible opportunity. For queries or further information please contact the Copyright Team, First Floor, 9 Hills Road, Cambridge CB2 1GE. OCR is part of the Cambridge Assessment Group; Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.OCR 2012<br />

Show answer