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. Al...
Question 1 Report
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.
Answer Details
(a) H2SO4 added to barium chloride solution
A white precipitate forms which is insoluble in excess acid. The precipitate is barium tetraoxosulphate(VI), BaSO4.
\(BaCl_2\text{(aq)} + H_2SO_4\text{(aq)} \rightarrow BaSO_4\text{(s)} + 2HCl\text{(aq)}\)
(b) Dilute HCl added to iron(II) sulphide (FeS)
Effervescence occurs and a colourless gas with an offensive, rotten-egg smell is evolved (hydrogen sulphide, H2S). The solid gradually dissolves.
\(FeS\text{(s)} + 2HCl\text{(aq)} \rightarrow FeCl_2\text{(aq)} + H_2S\text{(g)}\)
(c) Dilute HCl added to iron filings and left to stand
Effervescence (slow) with a colourless, odourless gas (hydrogen) evolved, and the solution gradually turns pale green as iron(II) chloride forms.
\(Fe\text{(s)} + 2HCl\text{(aq)} \rightarrow FeCl_2\text{(aq)} + H_2\text{(g)}\)
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