Question

Phosphorus reacts with chlorine gas to give a colourless liquid, which fumes in moist air to produce $HCl$ and

• A. $POC{l}_3$
• B. $H_{3}P{O}_3$
• C. $P{H}_3$
• D. $H_{3}P{O}_4$

Answer 1

Answer: (B)

Phosphorus reacts with chlorine gas to give phosphorus trichloride, $PC{l}_3$ which is a colourless liquid. Fumes of $PC{l}_3$ in moist air produces $HCl$ and phosphorous acid, $H_{3}P{O}_3$.
$P_4+C{l}_2\to \underset{\text{Colourless liquid}}{PC{l}_3}\underset{\text{Moisture}}{\overset{H_{2}O}{\to }}{H}_{3}P{O}_3+HCl$