Name :

(a) a nitrate of metal which on heating does not give nitrogen dioxide.

(b) a nitrate which on heating leaves no residue behind.

(c) a metal nitrate which on heating is changed into metal oxide.

(d) a metal nitrate which on heating is changed into metal.

(e) a solution which absorbs nitric oxide.

(f) the oxide of nitrogen which turns brown on exposure to air. How is it prepared?

(g) the gas produced when copper reacts with conc. HNO₃.

(a) Sodium nitrate
2NaNO₃ $\xrightarrow{\Delta}$ 2NaNO₂ + O₂↑

(b) Ammonium nitrate
NH₄NO₃ $\xrightarrow{\Delta}$ N₂O + 2H₂O

(c) Calcium nitrate
2Ca(NO₃)₂ $\xrightarrow{\Delta}$ 2CaO + 4NO₂ + O₂

(d) Silver nitrate
2AgNO₃ $\xrightarrow{\Delta}$ 2Ag + 2NO₂ + O₂

(e) Freshly prepared ferrous sulphate
6FeSO₄ + 3H₂SO₄ + 2HNO₃ (dil.) ⟶ 3Fe₂(SO₄)₃ + 4H₂O +2NO

FeSO₄ + NO ⟶ FeSO₄.NO

(f) Nitric oxide
2NO + O₂ ⟶ 2NO₂ (brown gas)

Nitric oxide can be prepared by catalytic oxidation of ammonia as shown below:

$4\text{NH}$3 + 5\text{O}2 \xrightarrow[700-800 \degree\text{C}]{\text{Pt}} \text{4NO} + \text{6H}_\text{2}\text{O} + 21.5 \text{K cals}

(g) Nitrogen dioxide
Cu + 4HNO₃ ⟶ Cu(NO₃)₂ + 2H₂O + 2NO₂