Question

For the water gas reaction:
$C_{\left(s\right)}+H_2{O}_{\left(g\right)}\rightleftharpoons C{O}_{\left(g\right)}+H_{2\left(g\right)},$
the standard Gibbs energy of reaction (at 1000 K) is $-8.1kJmo{l}^{-1}.$ What will be the equilibrium constant for the reaction? $log2.648=0.4229$

• A. $2mol{L}^{-1}$
• B. $4.8mol{L}^{-1}$
• C. $3.5mol{L}^{-1}$
• D. $2.648mol{L}^{-1}$

Answer 1

The correct option is D $2.648mol{L}^{-1}$

Given:
T = 1000 K
$\Delta G^o=-8.1kJmo{l}^{-1}$
Relation between standard Gibb's free energy and equilibrium constant for a reaction at constant temperature is given by,
$\Delta G^o=-2.303RTlog{K}_C$
$-8.1\times {10}^3=-2.303\times 8.314\times 1000log{K}_C$
$-8.1\times {10}^3=-19147.142log{K}_C$
$log{K}_c=0.423$
$K_c=2.648mol{L}^{-1}$