This question was attempted by majority of the candidates and the performance was fair
In (a)(i) I – III, most candidates displayed ignorance of the class of organic compound that could be identified with each of the given reagents and hence, could not state what would be observed in each case in (a)(ii) I – III.
The expected answers were
(a) (i) I alkenes/alkynes (unsaturated bydrocarbons)
II reducing sugars
III alkanoic acids
(ii) I. Bromine water – decolourization
II. Benedict’s solution – brick red precipitate
III. NaHCO3 - Effervescence/evolution of a gas.
In (b), candidates were able to name two gases that should be prepared in a fume chamber however, some of the candidates lost marks because they could not give a reason for their answer. The expected response was any two gases out of chlorine/ammonia/hydrogen-
chloride gas/carbon (II) oxide/sulphur(IV)oxide/nitrogen(IV) oxide because they are poisonous/have offensive smell/are dangerous to health.
In (c), candidates lost marks because they did not adhere to instructions by using names of indicators instead of P, Q and R.
The expected answers were
(i) P, Q and R
(ii) P
(iii) R