Question

At a particular temperature, the reaction below has a K value of 2.23 x 10-4.

2 AsH3(g)  ⇋ 2As(s) +3 H2(g)

Calculate K for the reaction:

2/3 As(s) +  H2(g) ⇋  2/3 AsH3(g)

2.23 x 10-4

16.5

4.48 x 103

6.06 x 10-2

9.02 x 1010

Answer 1

2 AsH3(g)  ⇋ 2As(s) +3 H2(g)         K   = 2.23 x 10-4.

K    = [As]^2[H2]^3/[AsH3]^2

1/K    = [AsH3]^2/[As]^2[H2]^3

2/3 As(s) +  H2(g) ⇋  2/3 AsH3(g)

K2    = [AsH3]^2/3/[As]^2/3 [H2]

K2   ={ [As]^2[H2]^3/[AsH3]^2 }^1/3

         =    (1/K)^1/3

            = (1/2.23*10^-4)^1/3

           =   (4484.3)^1/3

           =   16.5 >>>>answer

2/3 As(s) +  H2(g) ⇋  2/3 AsH3(g)    K = 16.5