CAIE A Level Chemistry 9701 · Hydrocarbons
Ethene can be converted into ethane by hydrogenation. Describe the reagents and conditions needed for this reaction, and outline the mechanism of the free-radical substitution of ethane by chlorine in ultraviolet light. Include the equations for the three stages of the mechanism.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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