question_answer

Identify the correct statement for change of Gibbs energy for a system \[(\Delta {{G}_{system}})\] at constant temperature and pressure:                                                                                                                         [AIPMT (S) 2006]

A)   If \[\Delta {{G}_{\text{system}}}>0,\] the process is spontaneous

B)        If \[\Delta {{G}_{\text{system}}}=0,\] the system has attained equilibrium

C)        If \[\Delta {{G}_{\text{system}}}=0,\] the system is still moving in a particular direction

D)        If \[\Delta {{G}_{\text{system}}}<0,\] the process is not spontaneous

Correct Answer: B

Solution :

If the Gibbs free energy for a system  is equal to zero, then system is present in equilibrium at a constant temperature and pressure.