Chemistry 9701 · AS & A Level · Hydrocarbons

Hydrocarbons — practice question

A, B and C each have the formula $\text{C}_4\text{H}_8$. Each one decolourises bromine, and they are structural isomers of one another.
(a)[1]

State the process by which A, B and C could be obtained from $\text{C}_{10}\text{H}_{22}$.

(b)[1]

Draw the structures for these three structural isomers.

(c(i))[2]

Only A exhibits geometrical isomerism. Explain what is meant by the term geometrical isomerism.

(c(ii))[4]

Draw the displayed formula of A, then use it to demonstrate the mechanism for the reaction between A and HBr. Include every required charge, dipole, lone pair and curly arrow.

(d(i))[1]

State what is meant by the term chiral centre.

(d(ii))[1]

Name compound B.

(d(iii))[2]

X occurs as a pair of optical isomers. Draw these isomers in the conventional three-dimensional representation.

(d(iv))[2]

Explain why X is obtained in a higher yield than Y.

(e(i))[1]

Name compound C.

(e(ii))[2]

Draw the displayed formula for each structural isomer formed in the reaction of C with $\mathrm{HBr}$.

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