Question

Identify the anion present in the following compound.

A salt D on treatment with dilute sulphuric acid produces a gas that turns lime water milky but has no effect on acidified potassium dichromate solution.

Answer 1

• When dilute Sulphuric acid (${\mathrm{H}}_2{\mathrm{SO}}_4$) is added to sodium carbonate(${\mathrm{Na}}_2{\mathrm{CO}}_3$) and heated, a colourless, odorless gas is evolved.
• The gas that evolved is carbon dioxide i.e., ${\mathrm{CO}}_2$​.
• When ${\mathrm{CO}}_2$is passed through lime water, it turns milky due to the formation of calcium carbonate (${\mathrm{CaCO}}_3$).
• Also, this gas doesn't show any effect when passed through acidified potassium dichromate (${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$)​ solution.