Edexcel Jan 2016 (IAL) Paper 5 Q20

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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 20 This question is about the naturally occurring substance, 2-hydroxybenzoic acid, which can be extracted from the bark of willow trees. OH OH (a) Give the molecular formula of 2-hydroxybenzoic acid. (b) The presence of the carboxylic acid group in 2-hydroxybenzoic acid is shown by the fact that it neutralizes sodium carbonate solution. Write the equation for this neutralization. State symbols are not required. (c) The 2-hydroxybenzoic acid forms a hydrogen bond within the molecule. (i) Complete the formula below to show this hydrogen bonding by displaying all the remaining atoms and bonds. *(ii) Will the melting temperature of 4-hydroxybenzoic acid be higher or lower than that of 2-hydroxybenzoic acid? Justify your answer. (1) (2) (1) (2) A E R A S I H T N I E T I R W T O N O D*P46941A01128* 11 Turn over<br /> (d) Phenol and 2-hydroxybenzoic acid react with excess bromine water in a similar way. Suggest the structural formula and name of the organic product formed when excess bromine water reacts with 2-hydroxybenzoic acid. (2) Name(e) The main chemical present in oil of wintergreen is methyl 2-hydroxybenzoate which is a liquid at room temperature. O OCH3 OH 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 (i) Give the chemicals and conditions needed to prepare methyl 2-hydroxybenzoate from 2-hydroxybenzoic acid in a single step reaction. (2) N T H I S A R E A12 *P46941A01228* 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 *(ii) Because methyl 2-hydroxybenzoate is sparingly soluble in water, it is extracted from the reaction mixture using ethyl ethanoate. Explain why methyl 2-hydroxybenzoate is sparingly soluble in water. (3)(iii) The solution of methyl 2-hydroxybenzoate in ethyl ethanoate is washed and then dried. Suggest the chemicals needed for these steps. Justify your suggestions. (3)(iv) State how methyl 2-hydroxybenzoate is separated from ethyl ethanoate. (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 *P46941A01328* 13 Turn over<br /> (v) The identity of methyl 2-hydroxybenzoate can be confirmed by infrared spectroscopy. Which of the infrared spectra below is given by methyl 2-hydroxybenzoate and which by 2-hydroxybenzoic acid? Justify your answer by identifying the bond responsible for a distinguishing absorption. Give the wavenumber range for this absorption. (2) Spectrum A 100 50 ( e c n a t t i m s n a r T 0 4000 3000 2000 1500 1000 500 Wavenumber / cm1 Spectrum B 100 50 ( e c n a t t i m s n a r T 0 4000 3000 2000 1500 1000 500 Wavenumber / cm1 14 *P46941A01428* 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 /> (vi) Calculate the volume of methyl 2-hydroxybenzoate produced from 9.00 g of 2-hydroxybenzoic acid, assuming the yield for this reaction is 60%, and the other reagents are present in excess. DATA Molar mass of 2-hydroxybenzoic acid = 138 g mol1 Molar mass of methyl 2-hydroxybenzoate = 152 g mol1 Density of methyl 2-hydroxybenzoate = 1.174 g cm3 (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 (Total for Question 20 = 22 marks) *P46941A01528* 15 Turn over<br />

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