Edexcel Jun 2017 (IAL) Paper 2 Q22

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22 This is a question about alcohols. (a) There are two alcohol structural isomers with the molecular formula, C3H8O. Give the skeletal formula of these isomers, their systematic names and the classification of the type of alcohol in each case. (3) Skeletal formula Name Classification (b) Ethanol can be oxidised by acidified sodium dichromate(VI) to ethanal and then to ethanoic acid. The apparatus may be set up in two ways. Reflux apparatus Distillation apparatus open top Liebig condenser water in water out pear-shaped flask thermometer Liebig condenser distillate anti-bumping granules anti-bumping granules round bottomed flask HEAT HEAT 14 *P48383A01424* 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 (i) Complete the ionic half-equation for the reduction of the dichromate(VI) ions to chromium(III) ions. State symbols are not required. Cr2O7 2 +H+ +(cid:111)+(ii) Describe how the reflux apparatus ensures that any ethanal initially produced is further oxidised to ethanoic acid. (2) (1)(iii) The distillation apparatus effectively separates ethanal from ethanol because of the large difference in boiling temperatures, which is a result of the hydrogen bonding between the molecules in ethanol. A E R A S I H T N I E T I R W T O N O D Compound Boiling temperature / (cid:113)C Ethanol, CH3CH2OH Ethanal, CH3CHO 79 21 Draw a hydrogen bond between two ethanol molecules. Clearly indicate any relevant dipoles and lone pairs of electrons. Label the bond angle about the hydrogen involved in the hydrogen bond and give its value. (3) A E R A S I H T N I E T I R W T O N O D *P48383A01524* 15 Turn over<br /> (iv) Explain why hydrogen bonds do not form between ethanal molecules. (1)(c) Alcohols can be converted into halogenoalkanes. (i) Write the equation for the reaction between methanol, CH3OH, and phosphorus(V) chloride, PCl5. (ii) State the experimental observation from this reaction. (1) (1)*(iii) Chloroethane can be made from a mixture of ethanol, potassium chloride and concentrated sulfuric acid. Explain why chloroethane can be made in this way, but iodoethane cannot be made from a similar mixture using potassium iodide instead of potassium chloride. You may use equations to support your explanation. (3)16 *P48383A01624* 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) Alcohols can be produced from the reaction of halogenoalkanes with aqueous alkali. (i) Draw the mechanism for this reaction with 1-bromopropane. Show the lone pair involved in the mechanism and any relevant dipoles and curly arrows. (3) (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 (ii) The reaction of 1-bromopropane with concentrated alcoholic alkali forms a different organic product. Name the type of reaction and give the displayed formula of the product. Name of reactionDisplayed formula of product A E R A S I H T N I E T I R W T O N O D *P48383A01724* 17 Turn over<br /> (e) How would you test for the OH group in 2-methylpropan-2-ol without using phosphorus(V) chloride? Name the reagent and state the observation for a positive test. (2)D O N O T W R I T E I N T H I S A R E A(Total for Question 22 = 22 marks) TOTAL FOR SECTION B = 38 MARKS 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 18 *P48383A01824*<br />

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