Question

What may be expected to happen when phosphine gas is mixed with chlorine gas?
(a) The mixture only cools down
(b) PCl₃ and HCl are formed and the mixture warms up
(c) PCl₅ and HCl are formed and the mixture cools down
(d) PH₃∙Cl₂ is formed with warming up.

Answer 1

(c) : Phosphine burns in the atmosphere of chlorine and forms phosphorus pentachloride.
PH₃ + 4Cl₂ → PCl₅ + 3HCl