Question

For the reaction taking place at certain temperature
$\ce{NH_2 COONH_4 (s) <=> 2NH_3 (g) + CO_2 (g) }$, if equilibrium pressure is 3X bar then $ \Delta_G$ would be

• A. - RT ln 9 - 3RT ln X
• B. RT ln 4 - 3RT ln X
• C. - 3RT ln X
• D. None of these

Answer 1

Answer: (D)

$N H _{2} C O O N H _{ 4 } \rightarrow 2 N H _{3}+ C O _{2}$
$2 X+X=3 X $
$K=2 X^{2} \times X=4 X^{3}$
Standard gibb's free energy $=-R T \times \ln K$
$\Delta G^{\circ}=-R T \times \ln 4 X^{3} $
$\Delta G^{\circ}=-3 R T \ln 4 X$