`100 mL` of phosphine `(PH_(3))` on hearing forms phosphorous `(P)` and hydrogen `(H_(2))`. The volume change in the reaction is

Options

A. a decrease of `50 mL`
B. an increase of `100 mL`
C. an increase of `150 mL`
D. an increase of of `50 mL`

Answer

D

Explanation

`underset(2 vol)underset(2 mol)(2PH_(3)(g)) rarr underset(3 vol)underset(2 mol)(2P(s)) + 3H_(2)(g)` (`v prop n`, according to Avogadro's law)
According to equation, `2 mL, PH_(3)` yields `3 mL. H_(2) (g)` leading to an increase of `1 mL`
Hence, `1mL. PH_(3)` will lead to an increase of `1//2 mL` and `100 mL. PH_(3)` will cause increase of `50 mL`