Question

[4]
Question 6.
(a) Identify the gas evolved and give the chemical test in each of the following cases:
(i) Dilute hydrochloric acid reacts with sodium sulphite.
(ii) Dilute hydrochloric acid reacts with iron(!!) sulphide.
(b)ldentify the cations in each of the following case:
[3]
(i) NaOH solution when added to the solution A gives areddish brown precipitate.
(ii) NH4OH solution when added to the solution B gives white ppt. which does not dissolve in
excess.
(iii) NaOH solution when added to solution C gives white ppt which is insoluble in excess.
(c) Complete and balance the following reactions:
[3]
(i) NaHCO3 + HCI ---- →
(ii) NaNO3 + Ca(OH)2 -->
(iii) NH3 + CuO ---→
**
**​

Answer 1

Answer:

(i) Sulphur-di-oxide gas is evolved. Colourless, gas with smell of burning sulphur. It turns acidified potassium dichromate orange to green.

(ii) Hydrogen sulphide gas is evolved. Colourless gas with smell of rotten eggs. It turns lead acetate paper black.

(i) Fe

3+

with NaOH gives reddish brown precipitate of Fe(OH)

3

.

(ii) Pb

+2

with NH

4

OH gives gelatinous white precipitate of Pb(OH)

2

.

(iii) Ca

+2

with NaOH gives white precipitate of Ca(OH)

2

which dissolves in excess