Question:
On reaction with Cl2, phosphorus forms two types of halides ‘A’ and ‘B’. Halide A is a yellowish-white powder but halide ‘B’ is a colourless oily liquid. Identify A and B and write the formulas of their hydrolysis products.
Solution:
Halide A is PCl5 because it is a yellowish-white powder
Halide B is PCl3 because it is a colourless oily liquid.
PCl3 + 3H2O H3PO3 + 3HCl
PCl5 undergoes a violent hydrolysis
PCl5 + H2O POCl3 + 2HCl
PCl5 + 4H2O H3PO4 + 5HCl