Chemistry 9701 · AS & A Level · 4.4

4.4 — practice question

Fig. 4.1 presents one possible route for synthesising propene, $\mathrm{C_3H_6}$: $\mathrm{C_2H_5COOH} \rightarrow \mathrm{C_2H_5CH_2OH} \rightarrow \mathrm{C_2H_5CH_2Cl} \rightarrow \mathrm{C_3H_6}$.
(a(i))[1]

Identify the kind of reaction that takes place in reaction 1.

(a(ii))[1]

Suggest a suitable reagent for reaction 2.

(a(iii))[2]

Reaction 3 is an elimination reaction. Write an equation for this reaction and state the solvent and conditions used.

(a(iv))[1]

$\mathrm{C_2H_5CH_2OH}$ can be converted directly into $\mathrm{C_3H_6}$. Suggest the reagent and conditions for this conversion.

(b(i))[1]

Under suitable conditions, propene polymerises to form poly(propene). Poly(propene) exhibits stereoisomerism. Identify the type of polymerisation that converts propene into poly(propene).

(b(ii))[2]

Define stereoisomerism.

(b(iii))[3]

Draw a section of poly(propene), showing two repeat units. Use your diagram to identify the type of stereoisomerism shown by poly(propene). Explain your answer.

(b(iv))[2]

State two difficulties linked to the disposal of poly(propene).

(c(i))[1]

Under different conditions, two molecules of propene can combine to form compounds X and Y. Name X.

(c(ii))[1]

Fig. 4.2 shows the mass spectrum of either compound X or compound Y. Identify which of X and Y gives this mass spectrum. Give one reason for your answer, referring to the fragmentation pattern.

(c(iii))[1]

In the spectrum in Fig. 4.2, the molecular ion peak has relative abundance 34.7. Calculate the relative abundance of the $[\mathrm{M}+1]^+$ peak in this spectrum.

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