$A$ reverberatory furnace is employed in the metallurgical process mainly for

Which of the following changes is not observed when an ore is heated for calcination?

Which of the following reactions is common for both self-reduction and carbon reduction when $Pb$ is extracted from galena $(PbS)$?

Reduction for which ore should be partially roasted is

The major products of the following reaction,$2ZnS_{(s)} + 3O_{2(g)} \xrightarrow{\text{Heat}} \dots$ are

Roasting of sulphides gives the gas $X$ as a byproduct. This is a colourless gas with a choking smell of burnt sulphur and causes great damage to 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.
The gas $X$ is