Chemistry 9701 · AS & A Level · Hydroxy compounds

Hydroxy compounds — practice question

$X$ has the structure $\text{CH}_3\text{CH(OH)CH}_2\text{CH}_3$.
(a)

A yellow precipitate is formed when $X$ reacts with alkaline aqueous iodine.

(a(i))[1]

Give the name of the yellow precipitate produced in this reaction.

(a(ii))[1]

Give the name by which $X$ is known.

(b)[2]

Three structural isomers of $X$ are alcohols. Draw the structures of all three alcohol isomers of $X$.

(c)

The reactions of $X$ are illustrated as follows: $\text{CH}_3\text{CH(OH)CH}_2\text{CH}_3 \xrightarrow{\text{reaction 1}} \text{CH}_3\text{COCH}_2\text{CH}_3$ and $\text{CH}_3\text{CH(OH)CH}_2\text{CH}_3 \xrightarrow{\text{reaction 2}} \text{C}_4\text{H}_8$.

(c(i))[1]

Identify the type of process occurring in reaction 1.

(c(ii))[1]

Identify the reagents used for reaction 1.

(c(iii))[3]

Reaction 2 may be done by passing the vapour of $X$ over hot aluminium oxide. The product of reaction 2, $\text{C}_4\text{H}_8$, is actually a mixture of three isomers. Give the full names of the three isomers produced in reaction 2.

(d(i))[4]

When methylpropene, $(\text{CH}_3)_2\text{CCH}_2$, reacts with hydrogen bromide, $\text{HBr}$, a mixture of two halogenoalkanes is produced. The major product is 2-bromo-2-methylpropane, while 1-bromo-2-methylpropane is formed only in small amounts. Complete the mechanism for the reaction of methylpropene with $\text{HBr}$ to make the major product. Include the intermediate structure and every required charge, dipole, lone pair and curly arrow. The structure of 2-bromo-2-methylpropane is not needed.

(d(ii))[2]

Explain why 2-bromo-2-methylpropane is the main product of this reaction.

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