Question

White phosphorus reacts with thionyl chloride to give ______.

Options

• PCl₅, SO₂ and S₂Cl₂

• PCl₃, SO₂ and S₂Cl₂

• PCl₃, SO₂ and Cl₂

• PCl₅, SO₂ and Cl₂

Answer 1

White phosphorus reacts with thionyl chloride to give PCl₃, SO₂ and S₂Cl₂.

Explanation:

White phosphorus (P₄) reacts with thionyl chloride (SOCl₂) to form phosphorus trichloride (PCl₃) along with the by-products sulphur dioxide (SO₂) and disulphur dichloride (S₂Cl₂):

\[\ce{P4 + 8SOCl2 -> 4PCl3 + 4SO2 + 2S2Cl2}\]

This reaction shows that phosphorus undergoes chlorination and oxidation simultaneously.