Chemistry 9701 · AS & A Level · An introduction to A Level organic chemistry

An introduction to A Level organic chemistry — practice question

Fig. 7.1 shows the structure of compound $\text{P}$.
(a(i))[1]

$\text{P}$ is optically active. Put an asterisk (*) next to every chiral carbon atom on the structure of $\text{P}$ in Fig. 7.1.

(a(ii))[2]

Pass plane polarised light through a pure sample of one enantiomer of $\text{P}$. Repeat this with a pure sample of the other enantiomer of $\text{P}$. Describe what happens in the two tests, including both the similarities and the differences.

(b(i))[1]

$\text{P}$ can be used to make compound $\text{Q}$ in a single step reaction. Give the structural formula of the compound added to $\text{P}$ to make $\text{Q}$ and give the formula of the other product in this reaction. Compound added to $\text{P}$. Other product.

(a)

The structure of compound $P$ appears in Fig. 7.1.

(b)

$P$ can be used to produce compound $Q$ in one step.

(b(ii))[3]

If an ester is treated with LiAlH$_4$ in dry ether, the ester bond is split by the addition of four hydrogen atoms and two alcohols are formed. Draw the structures of the compounds produced when $Q$ is treated with excess LiAlH$_4$ in dry ether.

(b(iii))[3]

Compare the relative basicities of compound $P$, compound $Q$ and phenylamine. least basic < ........................ < .......................... most basic Explain your answer.

(c)

$P$ can be used to make compound $R$ in a two-step reaction, as illustrated in Fig. 7.2.

(c(i))[2]

Identify the reagents and conditions used in the two stages of the reaction. step 1 ............................................................... step 2 ...............................................................

(c(ii))[2]

Complete Table 7.1 by drawing the structures of the organic products formed when $R$ is treated separately with the reagents shown. reagent: HNO$_2$(aq) at $4\,^{\circ}\text{C}$ reagent: an excess of Br$_2$(aq) at room temperature

(d)

$P$ can be used to make compound $T$.

(d(i))[1]

$T$ has a property in aqueous solution called an isoelectric point. Explain what is meant by isoelectric point.

(d(ii))[2]

$T$ can polymerise under suitable conditions. No other monomer takes part in this reaction. Draw part of the polymer chain formed that contains three $T$ monomers. Identify the repeat unit on your diagram.

Worked solution & mark scheme

This 17-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct chiral centre identified

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