Question

In aqueous solution, the liquid that absorbs nitric oxide to a considerable extent is
A.Lead nitrate
B.Nitric acid
C.Ferrous sulphate
D.Sodium hydroxide

Answer 1

When nitric oxide is absorbed in the aqueous solution, a brown coloured ring is formed. The reaction is used as a test to identify the presence of nitrate ions.

Complete step by step answer:
The absorption of nitric acid is done by the aqueous solution of ferrous sulphate $\left( {{\text{FeS}}{{\text{O}}_{\text{4}}}} \right)$. In the reaction, a brown coloured solution is obtained.
The reaction is as follows:
$\left[ {{\text{Fe}}{{\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right)}_{\text{6}}}} \right]{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + NO }} \to {\text{ }}\left[ {{\text{Fe}}{{\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right)}_{\text{6}}}\left( {{\text{NO}}} \right)} \right]{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{H}}_2}{\text{O}}$
The brown coloured solution is due to the formation of the complex $\left[ {{\text{Fe}}{{\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right)}_{\text{6}}}\left( {{\text{NO}}} \right)} \right]{\text{S}}{{\text{O}}_{\text{4}}}$. The complex formed is unstable and can readily dissociate on heating.
The solubility of nitric oxide in the aqueous solution of ferrous sulphate increases as the concentration of the ferrous sulphate in the solution increases.

Thus, the correct option is option (C).

Additional Information:
Nitric oxide is a colourless gas. It gets oxidized easily and forms nitrogen dioxide which is acidic and highly corrosive. Nitrogen dioxide has adverse effects on health and also on the environment.
The primary sources of nitric oxide are the combustion processes of fuels. The lightening and microbial actions in the soil are a natural source of nitric oxide.
Other ways to remove nitric oxide are:
1.Elimination at the source
2.Absorption by bacteria
3.Destruction by ultraviolet light

Note: The brown ring test is done to determine the presence of nitrate ion in any chemical compound.
Take aqueous solution of nitrate. Add iron sulphate to it. Add concentrated sulphuric acid slowly. At the junction of two layers, a brown coloured ring is observed. The brown ring indicates the presence of nitrate ions.