Answer : The initial concentration of HI and concentration of [tex]HI[/tex] at equilibrium is, 0.27 M and 0.386 M respectively.
Solution : Given,
Initial concentration of [tex]H_2[/tex] and [tex]I_2[/tex] = 0.11 M
Concentration of [tex]H_2[/tex] and [tex]I_2[/tex] at equilibrium = 0.052 M
Let the initial concentration of HI be, C
The given equilibrium reaction is,
[tex]H_2(g)+I_2(g)\rightleftharpoons 2HI(g)[/tex]
Initially 0.11 0.11 C
At equilibrium (0.11-x) (0.11-x) (C+2x)
As we are given that:
Concentration of [tex]H_2[/tex] and [tex]I_2[/tex] at equilibrium = 0.052 M = (0.11-x)
0.11 - x = 0.052
x = 0.11 - 0.052
x = 0.058 M
The expression of [tex]K_c[/tex] will be,
[tex]K_c=\frac{[HI]^2}{[H_2][I_2]}[/tex]
[tex]54.3=\frac{(C+2(0.058))^2}{(0.052)\times (0.052)}[/tex]
By solving the terms, we get:
C = 0.27 M
Thus, initial concentration of HI = C = 0.27 M
Thus, the concentration of [tex]HI[/tex] at equilibrium = (C+2x) = 0.27 + 2(0.058) = 0.386 M