Edexcel Jun 2017 Paper 4 Q15

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SECTION B Answer ALL the questions. Write your answers in the spaces provided. 15 This question is about carbonyl compounds. (a) Carvone exists as two optical isomers. (i) Label the chiral carbon atom with an asterisk (*). (ii) Give the molecular formula of carvone. (1) (1)(iii) Complete the skeletal formula of the organic product formed when carvone reacts with excess bromine. (2) 10 *P48082A01028* 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 /> A E R A S I H T N I E T I R W T O N O D (b) Dihydrocarvone has the structure shown. (i) State why dihydrocarvone does not exhibit geometric isomerism. (1)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 (ii) Complete the skeletal formula of the organic product formed when dihydrocarvone reacts with hydrogen cyanide in the presence of potassium cyanide. (1) (iii) State the number of different proton environments in a molecule of dihydrocarvone. (1)(iv) Suggest one of the main absorbance ranges in the infrared spectrum of dihydrocarvone in the region 2500 to 1500 cm1 and identify the bond responsible. (1) BondRangecm1 *P48082A01128* 11 Turn over<br /> (c) Sodium tetrahydridoborate, NaBH4, acts as a source of H ions and is a reducing agent. Complete the mechanism for the reduction of propanone to propan-2-ol. (i) In Step 1, add the relevant dipole, a lone pair of electrons and curly arrows. Step 1 H3C CH3 H H3C O CH3 (ii) In Step 2, add a relevant lone pair of electrons and curly arrows. Step 2 (2) (1) CH3 H3C H3C O OH CH3 OH 12 *P48082A01228* 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) When propene, C3H6, reacts with ozone, O3, an ozonide is formed. The ozonide is then hydrolysed with water and zinc to form two carbonyl compounds. H3C + O3 H3C Zn, H2O H3C ozonide (i) Show how the reaction with ozone and subsequent hydrolysis can be used to distinguish between but-1-ene and but-2-ene, by giving the structures of the carbonyl products formed in each case. But-1-ene But-2-ene (ii) Give the structure of an alkene that produces ethanal and butanone when it reacts with ozone, and the product is hydrolysed with water and zinc. (2) (1) 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 *P48082A01328* 13 Turn over (Total for Question 15 = 14 marks)<br />

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