(a) A soluble chloride X reacted with a liquid Y on heating, to give gas Z which turned moist blue litmus paper red and fumed in moist air.
(i) Identity Y and Z
(ii) Give one chemical test to confirm that X is a chloride
(b)(i) State one laboratory use of calcium chloride.
(ii) Name one laboratory technique suitable for separating a mixture of iron filings and ammonium chloride without applying heat.
(iii) State the action of solutions of the following salts on litmus respectively: K\(_2\)CO\(_3\); NaNO\(_3\), AICl\(_3\), (NH\(_4\))\(_2\)SO\(_4\).
Explanation
(a)(i) Y is Conc. H\(_2\)SO\(_4\), Z is HCl\(_{(g)}\) or hydrogen chloride
(ii) Acidify a solution of X with dilute HNO\(_3\) and add AgNO\(_{3(aq)}\). White ppt. soluble in aqueous ammonia confirms the presence of chloride. E.g. add solution of X to Pb\(^{2+}\) solution to get a white ppt. soluble when hot, reappearing on cooing.
(b)(i) Used as a drying agent
(ii) Magnetization OR dissolution in water and filtration
(iii) K\(_2\)CO\(_3\) - turns red litmus blue/alkaline
NaNO\(_3\) - has no effect/neutral
AlCl\(_3\) - turns blue litmus red/acidic
(NH\(_4\))\(_2\)SO\(_4\) - turns blue litmus red/acidic