Ethene decolourises bromine water because it contains the C=C\mathrm{C{=}C}C=C functional group.
Which compound will also decolourise bromine water?
CH2=CHCH2CH2CH3\mathrm{CH_{2}{=}CHCH_{2}CH_{2}CH_{3}}CH2=CHCH2CH2CH3
CH3CH2CH2CH2CH3\mathrm{CH_{3}CH_{2}CH_{2}CH_{2}CH_{3}}CH3CH2CH2CH2CH3
CH3CH2CH2CH2OH\mathrm{CH_{3}CH_{2}CH_{2}CH_{2}OH}CH3CH2CH2CH2OH
CH3CH2CH2COOH\mathrm{CH_{3}CH_{2}CH_{2}COOH}CH3CH2CH2COOH
63 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.