State your observation when :
A glass rod dipped in NH₄OH soln. is brought near an open bottle containing conc. HCl

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.

Select the correct answer from A, B, C and D.

(i) Aqua regia is a mixture of :

A : Dilute hydrochloric and conc. nitric acid
B : Conc. hydrochloric and dilute nitric acid
C : One part of conc. hydrochloric acid and 3 parts of conc. nitric acid.
D : 3 parts of conc. hydrochloric acid and 1 part of conc. nitric acid

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.