Question
Which of the following options will be correct for the stage of half completion of the reaction : $$A \rightleftharpoons B?$$
A.
$$\Delta {G^ \circ } = 0$$
B.
$$\Delta {G^ \circ } > 0$$
C.
$$\Delta {G^ \circ } < 0$$
D.
$$\Delta {G^ \circ } = - RT\,\ln \,2$$
Answer :
$$\Delta {G^ \circ } = 0$$
Solution :
When the reaction is half completed, $$\left[ A \right] = \left[ B \right].$$
$${\text{Thus,}}\,K = \frac{{\left[ B \right]}}{{\left[ A \right]}} = 1$$
$$\therefore \Delta {G^ \circ } = - RT\,\ln \,K$$ $$ = - RT\,\ln \left( 1 \right) = 0$$