OCR A Jan 2010 Paper 2 Q6

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This question is about the six alcohols below. 14 butan-2-ol 2-methylpentan-3-ol propan-1-ol ethane-1,2-diol 2-methylpropan-2-ol propan-2-ol (a) Which alcohol is an example of a tertiary alcohol?[1] (b) Draw the skeletal formula for 2-methylpentan-3-ol. (c) Butan-2-ol and 2-methylpropan-2-ol are structural isomers. (i) What is meant by the term structural isomer ? [1][1] (ii) Draw another structural isomer of these two alcohols. [1] (d) Ethane-1,2-diol can be dissolved in water to act as an anti-freeze in car radiators. Explain why ethane-1,2-diol is very soluble in water.[2]OCR 2010<br />
 15 (e) Ethane-1,2-diol is heated under reflux with ethanoic acid and a small amount of H2SO4 catalyst. Compound A is formed with molecular formula C6H10O4. Draw the structure of compound A. (f) Butan-2-ol is heated with H2SO4 catalyst.A mixture of three alkenes forms, B, C and D. The alkenes B and C are stereoisomers. (i) Draw the structures of the two stereoisomers B and C. [2] [2] (ii) What type of stereoisomerism is shown by B and C?[1] (iii) Draw the structure of the other alkene, D, that is formed in this reaction.OCR 2010 [1] Turn over<br />
 (g) Alcohol E is one of the following alcohols. 16 butan-2-ol 2-methylpentan-3-ol propan-1-ol ethane-1,2-diol 2-methylpropan-2-ol propan-2-ol A student oxidises alcohol E by heating under reflux with excess acidified potassium dichromate(VI). An organic product F is isolated. The mass spectrum of the alcohol E is shown below. 100 80 60 40 20 relative intensity 0 10 15 20 25 30 35 m / z 40 45 50 55 60 The infrared spectrum of the organic product F is shown below. 100 transmittance 50 (%) 0 4000 3000 2000 1500 wavenumber / cm1 1000 500OCR 2010<br />
 17 Name or draw the structures of the alcohol E and the organic product F. Write an equation for the reaction of alcohol E with acidified potassium dichromate(VI).Use [O] to represent the oxidising agent, acidified potassium dichromate(VI). In your answer, you should make clear how each structure fits with the information given above.[7]OCR 2010 [Total: 19] Turn over<br />

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