Identify the correct statement for change of Gibbs energy for a system `(Delta G_("system"))` at constant temperature and pressure.

Options

A. If `DeltaG_("system")=0` the system has attained equilibrium
B. If `DeltaG_("system")=0,` the system is still moving in a particular direction.
C. If `DeltaG_("system")lt0`, the process is not sponataneous.
D. If `DeltaG_("system")gt0`, the process is not spontaneous.

Answer

A

Explanation

If `DeltaG_("system")=0` the system has attained equilibrium is right. In it alternative (d) is most confusing as when `DeltaG gt0`, the process may be spontaneous when it is coupled with a reaction which has `DeltaGlt0` and total `DeltaG` is negative so righ answer is (a).