Question

in the reaction X(g) +Y(g) =2Z(g) 2 mole of X, 1 mole of Y and 1 mole of Z are placed in 10 litre vessel and allowed to reach equilibrium. If final concentration of Z is 0.2M , then Kc for the given reaction is :
(a) 1.60
(6) 80/3
(c) 16/3
(d) None of these​

Answer 1

• Kc for the given reaction is 16/3

Given-

Initial moles of X = 2 moles

Initial moles of Y = 1 moles

Initial moles of Z = 1 moles

Final concentration of Z = 0.2 M

Reaction is -

                              X (g)        +       Y (g)  ⇄          2Z (g)

At t = 0                 2 moles           1 moles            1 moles

At t= t eq            (2-a) moles        (1-a) moles      (1+2a) moles

For this reaction Kc = (Z)²/(X) (Y)

Equilibrium concentration of Z is given 0.2 M. So,

1+2a /10 = 0.2

a = 1/2

Kc = (1+2a)²/(2-a)(1-a)

By putting the values we get-

Kc = (1 + 2×1/2)²/ (2-1/2) (1-1/2)

Kc = 16/3

Hence correct option is (c) 16/3.

Regards