OCR A Jun 2015 Paper 4 Q1

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Answer all the questions. 1 A student analysed a mixture of compounds found in red wine using gas chromatography followed by mass spectrometry (GC-MS). Two of the compounds found to be present in the mixture are shown below. CHO OH OCH3 OH compound A compound B (a) The column in the gas chromatogram is packed with solid beads coated with a liquid polymer. How does gas chromatography (GC) separate the compounds in the mixture?[1] (b) The mass spectrum (MS) of the first compound to emerge from the column is shown below. y t i s n e e v i t a e r 100 80 60 40 20 25 50 75 m / z 100 125 150 (i) Identify the compound responsible for this spectrum. Give a reason for your answer.[1]OCR 2015<br /> (ii) What does your answer to (b)(i) suggest about the interaction of this compound with the phases present in the column?[1] (c) In red wine, compound A slowly forms an ester. The formation of the ester can also be done in the laboratory, as shown in the flowchart below. Separate portions of compound A are used in the formation of the ester. (i) Complete the boxes in the flowchart below. CHO reagent(s) NaBH4 reaction 1 OH compound A CHO OH compound A COOH OH compound C ester [3] (ii) Give the mechanism to show the formation of compound C in reaction 1. Use curly arrows and relevant dipoles.OCR 2015 [3] Turn over<br /> (d) 1 mol of compound B reacts with 2 mol of bromine, Br2 by electrophilic substitution. OCH3 OH compound B Write a balanced equation for this reaction, showing clearly the structure of the organic compound. [1] [Total: 10]OCR 2015<br />

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