Oxidation of alcoholsAQA A-Level Chemistry: Mind map

Exam questions on Oxidation of alcohols

1. A school technician is given three unlabelled liquids, each with the molecular formula C₄H₁₀O: butan-1-ol, butan-2-ol and 2-methylpropan-2-ol. She warms a sample of each with acidified potassium dichromate(VI) solution.
   State the colour of the mixture after warming for butan-2-ol and for 2-methylpropan-2-ol, and explain each result.2 marks
2. Propan-1-ol can be converted into either propanal or propanoic acid using acidified potassium dichromate(VI), depending on how the apparatus is set up. In one experiment the alcohol is heated in a flask fitted with a distillation head and the product is collected as it forms. In a second experiment the mixture is heated under reflux with excess oxidising agent for a long time.
   Write two equations, using [O] to represent the oxidising agent, for the oxidation of propan-1-ol to propanal and then propanal to propanoic acid.2 marks
3. A forensic chemist has two colourless liquids, pentanal and pentan-2-one, which both have the molecular formula C₅H₁₀O. She tests a sample of each with warm Fehling's solution and with warm Tollens' reagent.
   Describe the observations the chemist would make when each liquid is tested with Fehling's solution and with Tollens' reagent.3 marks