What property of hydrogen chloride is demonstrated when it is collected by downward delivery [upward displacement]. Why is hydrogen chloride not collected over water.

Write equations for the reactions :

(i) dil. HCl and sodium thiosulphate.

(ii) dil. HCl and lead nitrate soln.

Match each substance A to E listed below with the appropriate description given below :

[A] Sulphur
[B] Silver chloride
[C] Hydrogen chloride
[D] Copper [II] Sulphate
[E] Graphite.

(i) A covalent compound which behaves like an ionic compound in aqueous solution.
(ii) A compound which is insoluble in cold water but soluble in excess of ammonia solution.

Write a balanced equation for each of the following :

(i) Red lead is warmed with concentrated hydrochloric acid.

(ii) Magnesium metal is treated with dilute hydrochloric acid.