At 700 K , the equilibrium constant for the reaction :
`H_2(g) + I_2(g) hArr 2HI(g)` is 54.8 . If 0.5 mol `L^(-1)` of HI(g) is present at equilibrium at 700 K, what are the concentration of `H_2(g)` and `I_2(g)` assuming that we initially started with HI(g) and allowed it to reach equilibrium at 700 K ?

Explanation

`{:(,2HI(g) hArr,H_2(g) +, I_2),("At equi.",0.5,x,x):}`
`K_c=([H_2][I_2])/[HI]^2=1/54.8`
`x^2/(0.5)^2=1/54.8`
`x^2=0.25/54.4.56xx10^(-3)`
x=0.068
`[H_2]=[I_2]="0.068 mol L"^(-1)`