Organic Chemistry Structured Questions | Cambridge O Level Chemistry

(a)

Hydrocarbons belong to various homologous series.

[4]

(i)

Define the term homologous series.

[2]

(ii)

State two general physical and chemical characteristics shared by members of any homologous series.

[2]

(b)

An unknown hydrocarbon X contains 85.7% carbon and 14.3% hydrogen by mass. The relative molecular mass (Mr) of X is 56. (Relative atomic masses: C = 12.0, H = 1.0)

[3]

(i)

Calculate the empirical formula of hydrocarbon X. Show your working clearly.

[2]

(ii)

Deduce the molecular formula of hydrocarbon X.

[1]

(c)

Hydrocarbon X exhibits structural isomerism.

[6]

(i)

Draw the displayed formulae and state the systematic IUPAC names of the two unbranched alkene isomers of X.

[3]

(ii)

Draw the displayed formula of one branched alkene isomer of X.

[1]

(iii)

Draw the displayed formula of a saturated cyclic isomer of X and explain why it does not decolourise aqueous bromine in the dark.

[2]