Edexcel Jun 2016 (IAL) Paper 4 Q

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SECTION C Answer ALL the questions. Write your answers in the spaces provided. 14 Butanedione has two carbonyl groups. It is a volatile yellow-green liquid and its colour is due to electron delocalisation. Butanedione can be reduced to butane-2,3-diol which does not have this electron delocalisation. (a) Identify a suitable reagent for this reduction and complete the equation for the reaction. ReagentCH3COCOCH3 +[H] (cid:111) butanedione butane-2,3-diol (b) Suggest what you would see when this reaction occurs. (3) (1)(c) (i) A mixture of butanedione and butane-2,3-diol can be separated by distillation. State which compound will have the higher boiling temperature. Justify your answer. (1)(ii) Explain why both compounds are soluble in water. (1)24 *P46664A02428* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br /> (d) Butane-2,3-diol shows a type of stereoisomerism that butanedione does not. State this type of stereoisomerism and describe how it arises. (2)(e) Butane-2,3-diol can be esterified using excess propanoic acid. (i) Suggest an alternative reagent to propanoic acid which would react with butane-2,3-diol to form the same ester. State two of the ways in which the esterification reaction will be different with the use of your chosen reagent. (3)(ii) Draw the skeletal formula of the ester produced from butane-2,3-diol and excess propanoic acid. (2) A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D *P46664A02528* 25 Turn over<br /> (f) Use the Data Booklet to state two differences between the infrared spectra of butanedione and butane-2,3-diol. Include the wave numbers of the relevant groups or bonds. (2)D O N O T W R I T E I N T H I S A R E A*(g) Use chemical shift data from the Data Booklet to sketch the high resolution proton nmr spectrum for propanoic acid. The peaks do not overlap. Explain the number of peaks, their splitting pattern and the ratio of the areas under each set of peaks. (5) 13 12 11 10 Chemical shift, (cid:303) / ppm 26 *P46664A02628* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br /> A E R A S I H T N I E T I R W T O N O D(h) State the type of radiation that is used to create the nmr spectrum. (1)(Total for Question 14 = 21 marks) TOTAL FOR SECTION C = 21 MARKS TOTAL FOR PAPER = 90 MARKS A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D *P46664A02728* 27<br />

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