Edexcel Jun 2016 (IAL) Paper 5 Q

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Answer ALL the questions. Write your answers in the spaces provided. 19 This question is about benzene and some of its compounds. SECTION B *(a) In 1865, Kekul suggested that the benzene molecule was a six-membered carbon ring with alternate double and single bonds. However, this suggestion did not fully explain the structure and stability of benzene. State and explain three different types of evidence that led to this structure of benzene being rejected, in favour of benzene with a ring of delocalised electrons. (3)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 *P46665A01132* 11 Turn over<br /> (b) Benzene reacts with a mixture of concentrated nitric acid and concentrated sulfuric acid to form nitrobenzene. (i) Give the mechanism for this reaction, including an equation for the formation of the electrophile. (4) (ii) The preparation of nitrobenzene is usually carried out between 50C and 60C. Explain why the temperature used should not be higher or lower. (2)12 *P46665A01232* 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 (c) Benzene reacts with pure bromine when heated under reflux in the presence of a Friedel-Crafts catalyst. Phenol reacts with bromine water at room temperature. (i) Write the equation for the reaction between phenol and excess bromine water. *(ii) Explain why phenol reacts with bromine under much milder conditions than those required for the reaction between benzene and bromine. (2) (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 *P46665A01332* 13 Turn over<br /> (d) 1-chloro-1-phenylethane is found in some fruits, such as apples, and is used to make fragrances. It can be synthesised from benzene in three steps. Step 1 Step 2 Compound X Step 3 Cl 1-chloro-1-phenylethane (i) Identify, by name or formula, the reagent and catalyst used in Step 1. (2)(ii) Draw the structure for Compound X. (iii) Identify, by name or formula, the reagent used in Step 2. (1) (1)(iv) Identify, by name or formula, the reagent used in Step 3. (1)(Total for Question 19 = 18 marks) 14 *P46665A01432* 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 A E R A S I H T N I E T I R W T O N O D BLANK PAGE A E R A S I H T N I E T I R W T O N O D *P46665A01532* 15 Turn over<br />

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