All your burette readings (initials and final) as well as the size of your pipette must he recorded but no account of experimental procedure is required. All calculations must be done in your booklet.
State the observation that would be made when each of the following reactions is carried out in the laboratory:
(a) Addition of 2 cm\(^3\) of bench H\(_2\)SO\(_{4(aq)}\) to 2 cm\(^{3}\) of barium chloride solution;
(b) Addition of 2 cm\(^3\) of dilute hydrochloric acid to 1g of powered iron(II) sulphide (FeS):
(C) Addition of 2 cm\(^3\) of dilute hydrochloric acid to 1g of iron filings and allowed to stand for sometime.
Explanation
(a) Observation made when 2cm\(^3\) of bench H\(_2\)SO\(_4\) was added to 2cm\(^3\) of barium chloride solution.
H\(_2\)SO\(_{4(q)}\) + BaCl\(_{2(aq)}\) \(\to\) BaSO\(_{4(s)}\)(white) + 2HCl\(_{(aq)}\)
White precipitate of BaSO\(_4\) Barium tetraoxosulphate(VI) is formed
(b) Observation made by the addition of dilute hydrochloric acid to 1g of powered iron (III) sulphide (FeS)
2HCl\(_{(aq)}\) + FeS\(_{(s)}\) \(\to\) FeCl\(_{(aq)}\) + H\(_2\)S\(_{(g)}\)
Effervescence (bubbling) occurs or evolution of a gas with a smell of rotten eggs and a green solution is formed.
(c) Observation made by the addition of 2cm\(^3\) of dillute hydrochloric acid to 1g of iron filings and allowed to stand for sometime
Effervescence or evolution of colourless, odourless gas noticed with the formation of light green solution that will turn brown after sometime.