What is the value of the equilibrium constant for the following reaction at 400 K ?
`2NOCl(g) hArr 2NO(g) + Cl_(2)(g)`
`Delta H^(@) = 77.5 kJ mol^(-1), R = 8.3124 J mol^(-1) K^(-1), Delta S = 135 J K^(-1) mol^(-1)`.

Explanation

`Delta G = Delta H - T Delta S`
`Delta G = 77.5 xx 1000 J - 400 K + 135 J K^(-1) = 77500 J - 54000 J = 23500 J`
`Delta G = -2.303 RT log K`
`23500J = -2.303 xx 8.314 xx 400 K log K`
`log K = (-23500)/(19.147 xx 400 K) = (-235)/(76.588) = -3.068`
K = Antilog (-3.608)
`"Antilog" (0.932 - 4) = "Antilog" (0.93) xx 10^(-4) = 8.55 xx 10^(-4)`.