Question

100 ml of PH₃ when decomposed produce phosphorus and hydrogen. The change in volume is

(a) 50 ml increase

(b) 500 ml decrease

(c) 900 ml decrease

(d) Nil

Answer 1

Correct option is (a) 50 ml increase

2PH₃ → 3H₂(g) + 2P(s)

Volume of H₂ formed = \(\frac 32\) x 100 = 150 ml.

Increase in volume = 150 - 100 = 50 ml.