Chemistry 5070 · O Level · Formulae, functional groups and terminology

Formulae, functional groups and terminology — practice question

The structure of Ester A is shown here.
(a)[1]

Give the name of ester A.

(b(i))[2]

Ester A reacts with hot aqueous sodium hydroxide to form two compounds, B and C. Compound B has the percentage composition by mass: 29.3% carbon; 3.7% hydrogen; 39.0% oxygen; 28.0% sodium. Calculate the empirical formula for this compound.

(b(ii))[2]

Compound C has a relative molecular mass of 74 and is oxidised by warm acidified potassium manganate(VII) to produce butanoic acid. Suggest a structure for C. Give reasons for your answer.

(c(i))[1]

What does the term isomerism mean?

(c(ii))[1]

Draw an isomer for ester A.

(d)[1]

Explain why ester A is a saturated compound.

(e(i))[1]

Ester A can be used as a fragrance or perfume because it diffuses easily. Explain why the rate of diffusion of the ester decreases as the temperature decreases.

(e(ii))[1]

Suggest one further use for ester A.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: butyl ethanoate or butyl acetate

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