This question is on theory of practical work. Majority of the candidates
that attempted this question did poorly.
Some of the candidates lost marks because they used formulae in identifying
the components instead of names.
Also, some candidates used wrong lettering of symbols of elements in writing out the equation. e.g. instead of ‘Cl’ some candidates wrote ‘CL’ and ‘NACL’ instead of
‘NaCl’ etc.
The expected answers include:
(i) P - Delivery tube
Q - Drying tower
R - Calcium oxide (accept quicklime)
S - Ammonia gas
T - Retort stand with clamp
(ii) Upward delivery (of gas)/ downward displacement of air
(iii) To dry the gas
(iv) Ca(OH)2(aq) + 2NH4Cl(aq) → CaCl2 + 2H2O + 2NH3(g)