Question

Which salt on heating with conc. $H_{2}S{O}_4$ gives violet vapours?

• A. Iodide
• B. Nitrate
• C. Sulphate
• D. Bromide

Answer 1

Answer: (A)

$KI+\underset{Conc.}{H_{2}S{O}_4}\stackrel{\Delta }{\to }KHS{O}_4+HI$

$\text{conc}\text{.}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{+ 2HI}\to \underset{\text{Violet}\text{vapours}}{{\text{2H}}_{\text{2}}{\text{O + I}}_{\text{2}}{\text{+ SO}}_{\text{2}}}$