Question

Hydrogen iodide can decompose into hydrogen and iodine gases. 2 HI(g) H2(g) + 12(g) Kp for the reaction is 0.016. If 0.350 atm of HI(g) is sealed in a flask, what is the total pressure of the system when equilibrium is established? a. 0.385 atm b. 0.350 atm c. 0.279 atm d. 0.258 atm e. 0.412 atm

Answer 1

Answer : The total pressure at equilibrium is 0.350 atm

Solution :  Given,

Initial pressure of $HI$ = 0.350 bar

$K_p$ = 0.016

The given equilibrium reaction is,

                             $2HI(g)\rightleftharpoons H_2(g)+I_2(g)$

Initially                  0.350           0       0

At equilibrium       (0.350-2x)    x       x

The total pressure at equilibrium = $(0.350-2x)+x+x=0.350-2x+2x=0.350atm$

Thus, the total pressure at equilibrium is 0.350 atm