OCR A Jan 2013 Paper 2 Q3

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3 Pentan-2-ol, shown below, is a secondary alcohol. OH (a) Pentan-2-ol can be converted into three alkenes, A, B and C, by the elimination of water. Two of the alkenes, A and B, are stereoisomers. The third alkene, C, is a structural isomer of both A and B. This elimination often uses a catalyst. (i) What is a suitable catalyst for this reaction?[1] (ii) Construct an equation, using molecular formulae, for the elimination of water from pentan-2-ol.[1] (iii) Explain what is meant by the terms structural isomers and stereoisomers. structural isomersstereoisomers[4]OCR 2013<br />
 (iv) In the boxes below: draw the structures of stereoisomers A and B draw the structure of isomer C. stereoisomer A stereoisomer B isomer C [3] (v) Stereoisomers A and B show E/Z isomerism. State two features of these molecules that enable them to show E/Z isomerism.[2] (b) Pentan-2-ol can be oxidised by heating under reflux with acidified aqueous potassium dichromate(VI). Complete the equation for this oxidation. Use a skeletal formula for the organic product. Use [O] to represent the oxidising agent. OHOCR 2013 [2] Turn over<br />
 (c) Pentan-1-ol can also be oxidised but it gives two different products. Complete the flowchart below to show the structures of the two organic products formed. CH3CH2CH2CH2CH2OH distil with H2SO4 / K2Cr2O7 heat under reflux with H2SO4 / K2Cr2O7 [2] [Total: 15]OCR 2013<br />
 BLANK PAGE Question 4 begins on page 10 PLEASE DO NOT WRITE ON THIS PAGEOCR 2013 Turn over<br />

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