Edexcel Jun 2017 (IAL) Paper 4 Q17

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17 This question is about some reactions of propanone. (a) Iodine reacts with propanone, CH3COCH3, in two different ways depending on the conditions. (i) Write the equation for the reaction between iodine and propanone in the presence of an acid catalyst. State symbols are not required. (ii) Suggest why the rate of this reaction increases as the reaction proceeds. (1) (1)(b) (i) Identify, by names or formulae, the organic products of the reaction between iodine and propanone in alkaline conditions. (2)(ii) Describe two observations you expect to make when this reaction occurs. (2)12 *P48385A01228* 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 /> (c) (i) When propanone reacts with lithium tetrahydridoaluminate(III), water is not a suitable solvent. Explain why water is unsuitable and name the solvent that should be used. (2)(ii) Draw the skeletal formula of the organic product of this reaction. (1) (d) Propanone reacts with 2,4-dinitrophenylhydrazine to form an organic product which is a crystalline solid and water. (i) Complete the formula of the crystalline solid. The formula of 2,4-dinitrophenylhydrazine can be simplified to RNHNH2 (1) R N N 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 *P48385A01328* 13 Turn over<br /> (ii) What are the two uses of 2,4-dinitrophenylhydrazine in the laboratory? (2)(e) (i) Propanone reacts with hydrogen cyanide to form a cyanohydrin, with structural formula (CH3)2C(OH)CN. D O N O T W R I T E I N T H I S A R E A Give the fully displayed formula and the systematic name for this compound. (2) Fully displayed formula D O N O T W R I T E I Systematic name(ii) Draw the mechanism for the reaction of propanone with hydrogen cyanide, in the presence of cyanide ions, to form the cyanohydrin, (CH3)2C(OH)CN. Use curly arrows to show the movement of electron pairs. (4) 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 14 *P48385A01428*<br /> *(iii) When hydrogen cyanide and propanone react in ethanol solution to form the cyanohydrin, an equilibrium is set up. CH3COCH3 + HCN (cid:85) (CH3)2C(OH)CN When 100 cm3 of 0.10 mol dm3 propanone solution is mixed with 100 cm3 of 0.20 mol dm3 hydrogen cyanide solution, the equilibrium concentration of the cyanohydrin is 0.034 mol dm3. Calculate the equilibrium constant K c for this reaction. Include units with your answer, which should be given to two significant figures. (4) (Total for Question 17 = 22 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 A E R A S I H T N I E T I R W T O N O D *P48385A01528* 15 Turn over<br />

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