Chemistry 5070 · O Level · Alcohols

Alcohols — practice question

A student uses the apparatus shown to determine the energy released by the combustion of each of three alcohols, X, Y and Z. In every experiment $0.1\text{ mol}$ of alcohol is burnt, and the water starts at $20\,^{\circ}\text{C}$.
(a(i))[2]

Use the thermometer readings to fill in the table and work out the rise in temperature in each experiment.

(a(ii))[1]

Deduce from these results the kind of reaction that is occurring.

(b(i))[2]

Calculate the empirical formula and hence the molecular formula of $Y$.

(b(ii))[3]

Using your answers to (a)(i) and (b)(i), suggest the formula of $X$ and the formula of $Z$, giving reasons for your choices.

(c(i))[1]

The student oxidises alcohol $Y$ to produce a carboxylic acid. Name this acid and give its structure.

(c(ii))[2]

Suggest the name of an oxidising agent that can be used and the colour change seen in the mixture during the reaction.

(d)[2]

Give the name and structure of the ester that may be formed by reacting alcohol $Y$ with the acid produced in (c)(i).

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: 32, 38, 44 with 20, 20, 20 below them

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