Answer : The equilibrium pressure of [tex]H_2(g)[/tex] is, 288 torr
Explanation : Given,
Initial pressure of [tex]AsH_3[/tex] = 392.0 torr
Total pressure = 488.0 torr
The balanced equilibrium reaction is,
[tex]AsH_3(g)\rightleftharpoons 2As(s)+3H_2(g)[/tex]
Initial pressure 392.0 0
At eqm. (392.0-2p) (3p)
The expression of equilibrium constant [tex]K_p[/tex] for the reaction will be:
[tex]K_p=\frac{(p_{H_2})^3}{(p_{AsH_3})}[/tex]
As,
Total pressure at equilibrium = (392.0-2p) + (3p) = 488.0 torr
(392.0-2p) + (3p) = 488.0
392.0 + p = 488.0
p = 488.0 - 392.0
p = 96
Thus, the equilibrium pressure of [tex]H_2(g)[/tex] = 3p = 3(96) = 288 torr
Therefore, the equilibrium pressure of [tex]H_2(g)[/tex] is, 288 torr