What this practice covers
These questions are drawn from past CIE 9701 Chemistry papers and filtered to hydrocarbons. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on hydrocarbons, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Leaving out the initiation or termination step, or forgetting to say UV light is needed.
- Writing free-radical substitution as a good way to make a pure halogenoalkane. It gives a mixture.
- Forgetting the induced dipole when bromine adds to an alkene.
- Drawing the curly arrow from the carbon rather than from the C=C bond.
- Predicting the anti-Markovnikov product for an unsymmetrical alkene.
- Saying bromine water is decolourised by alkanes. Only alkenes do it, which is why it is a test.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Hydrocarbons revision notes.