Addition reactions of alkenesEdexcel International A Level Chemistry: Mind map

Exam questions on Addition reactions of alkenes

1. Margarine manufacturers harden liquid vegetable oils, whose molecules contain C=C bonds, by reacting them with hydrogen gas in the presence of a nickel catalyst. Relative atomic masses are given where needed, and the molar volume of a gas at room temperature and pressure is 24.0 dm³ mol⁻¹.
   A student shakes a sample of the vegetable oil with bromine water. State the colour change and explain what it shows.2 marks
2. Ethanol for industrial use is made from ethene, which comes from the cracking of oil. Ethene also undergoes several other addition reactions that a chemist is investigating.
   Write the equation for the reaction of ethene with steam to make ethanol, and name a suitable catalyst.2 marks
3. A technician has two unlabelled colourless liquids, one hexane and one hex-1-ene. Separately, she studies the oxidation of propene by cold, dilute, acidified potassium manganate(VII).
   Describe a test that would identify which liquid is hex-1-ene, stating the observation for each liquid.3 marks