Question 3A
State what would be observed if the following reactions are carried out in the laboratory:
(i) methyl orange is dropped into a solution of lime juice;
(ii) hydrogen sulphide gas is bubbled through iron (III) chloride solution;
(iii) sulphur (IV) oxide gas is bubbled into acidified solution of KMnO4;
(iv) ethanoic acid is added to a solution of k2CO3.
Observation
This question tested familiarity of the candidates with the practical activities suggested in their teaching syllabuses
Majority of the candidates gave the correct colour change of methyl orange in lime juice. They equally gave correct observation when ethanoic acid is mixed with potassium trioxocarbonate (IV).
Expected answers include:
(i) The solution turns / pink (accept solution turns red )
(ii) The FeCl3 solution changes colour from brown to green and there is a yellow deposit (accept precipitate)
(iii) The purple colour turns colourless / is decolourised
(iv) There is effervescence colourless, odourless gas evolved