Part (a) was based on the concept of hydrolysis.  Most candidates attempted it and the responses were fair.  However, some candidates lost marks for Na2SO4(aq); which should be no effect on both red and blue litmus paper.  Majority of the candidates just wrote “no effect on litmus paper”.
In part (b), only few candidates mentioned pH meter and universal indicator as the methods for determining the pH of a solution.  Some candidates however lost marks because they wrote pH scale instead of pH meter and indicator paper instead of universal indicator paper or solution.
Part (c) was well attempted by most of the candidates.
Part (d) (i) Many candidates were able to state that chromatography is used to separate coloured                    mixture.

(ii)Many candidates exhibited the fact that they were not familiar with recrystallizatrion method.

(iii)Many candidates lost marks because they failed to specifically mention miscible liquids can be separated by fractional distillation.

The expected answers were:
Question 3
(a)     (i)         Na2SO4(aq)  -          No effect on both red and blue litmus papers

(ii)A1Cl3(aq)    -      Turns blue litmus red

(iii)K2S(aq).      -       Turns red litmus blue

(b)      *Universal indicator solution/paper method.
            *pH meter method.
(c)       (i)          Effervescence/colourless and odourless gas evolved.

(ii)Yellow precipitate formed.

(iii)Blue gelatinous precipitate formed in drops.  The blue precipitate dissolves in excess forming deep blue solution.

(d)  (i)  Chromatography – to separate components of dyes/plant leaf extracts/complex
coloured mixture.

(ii) Recrystallization – to purify solid chemical substances.

(iii)       Fractional distillation – to separate/purify mixture of two or more miscible liquids.