Question

Roasting of sulphides gives the gas X as a product. This is a colorless gas with a cooking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic and acts as a reducing agent and its acid has never been isolated. The gas X is:
A.${{H}_{2}}S$
B.$S{{O}_{2}}$
C.$C{{O}_{2}}$
D.$S{{O}_{3}}$

Answer 1

. This is a colourless gas with a choking smell of burnt sulphur and causes great damage to the respiratory organs as a result of acid rain. Its aqueous solution is acidic, acts as a reducing agent and its acid has never been isolated.

Complete step by step answer:
Roasting of sulphides gives us the gas $S{{O}_{2}}$ as a byproduct. This is a colorless gas that has a cooking smell of burnt sulphur and causes great damage to respiratory organs as a result of the acid rain. Its aqueous solution is acidic and does act like a reducing agent and its acid has never been isolated.
For example sulphur dioxide gas is obtained by roasting zinc blende or iron pyrites.
$2ZnS+3{{O}_{2}}\text{ }\to 2ZnO+2S{{O}_{2}}$
$4Fe{{S}_{2}}\text{ }+11{{O}_{2}}\text{ }\to 2F{{e}_{2}}{{O}_{3}}\text{ }+8S{{O}_{2}}$

Sulphur dioxide dissolves in water forming sulphurous acid. hence, it is known as sulphurous anhydride.
${{H}_{2}}O+S{{O}_{2}}={{H}_{2}}S{{O}_{3}}$

​It reduces chlorine to HCl.
$S{{O}_{2}}+C{{l}_{2}}\text{ }+2{{H}_{2}}O\to {{H}_{2}}S{{O}_{4}}\text{ }+2HCl$
Therefore it is $S{{O}_{2}}$ gas.

So, the correct answer is “Option B”.

Note: Sulfur dioxide or sulphur dioxide is the chemical compound with the formula $S{{O}_{2}}$. It is a very toxic gas which is the reason for the smell of burnt matches. It is released naturally by volcanic eruptions and is also produced as a by-product of copper extraction and the burning of fossil fuels is also contaminated with a good percentage of sulfur compounds. It is to be remembered that $S{{O}_{2}}$ is not a greenhouse gas, so it does not help in protection of the environment.
Molar mass of the gas is $64.066\text{ }gmo{{l}^{-1}}$
IUPAC name is Sulfur dioxide
Melting point: of the gas is ${{72}^{0}}C$
Boiling point of the gas is $-{{10}^{0}}C$