Question

The equilibrium constant $K_{p}$ for a homogenous gaseous reaction is $10^{- 3}$ . The standard Gibbs free energy change $\Delta G^\circ $ for the reaction at $27^\circ C$ (using R = 2 cal $K^{- 1}mol^{- 1}$ ) is

• A. 0
• B. -1.8 kcal
• C. -4.1454 kcal
• D. +4.1454 kcal

Answer 1

Answer: (D)

$\text{ΔG} \, \text{=} \, - \text{2} \text{.303} \, \text{RT} \, \text{log} \, \text{K}_{\text{p}}$
$= - 2.303 \times 2 \times 300 \, \text{log} \, 10^{- 3}$
$\text{=} - \text{2} \text{.303} \, \text{\times } \, \text{2} \, \text{\times } \, \text{300} \, \text{\times } \, \text{(} - \text{3)}$
$\text{=} \, \text{1445} \text{.4} \, \text{cal} \, \text{=} \, \text{4} \text{.1454} \, \text{kcal}$