JEE Main 2022 — Practical Chemistry Question with Solution

When small amount of carbonate salt is treated with dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ or dilute $\mathrm{HCl}$, A colourless, odourless gas $\left({\mathrm{CO}}_2\right)$ is evolved with brisk effervescence

When small amount of the following salts are treated with dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$  the following observations are seen.

${\mathrm{Na}}_2\mathrm{S}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{S}\uparrow$

NO^{2 –}  on reaction with dilute H₂SO₄ will give brown NO₂(g) will turn KI solution blue.

${\mathrm{SO}}_3^{2-}$on reaction with dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ will give ${\mathrm{SO}}_2\left(\mathrm{g}\right)$, which will turn acidified potassium dichromate solution green.