NEET2006ChemistryThermodynamics (C)Actual
Identify the correct statement for change of Gibbs energy for a system ( G _ system ) at constant temperature and pressure:
Options
- AIf G _ system < 0 , the process is not spontaneous
- BIf G _ system >0 , the process is spontaneous
- CIf G _ system =0 , the system has attained equilibrium
- DIf G _ system =0 , the system is still moving in a particular direction
Correct answer
C. If G _ system =0 , the system has attained equilibrium
Step-by-step solution
If the Gibbs free energy for a system ( G _ system ) is equal to zero, then the system is in equilibrium at constant temperature and pressure. Related Theory Free energy change criteria for predicting spontaneity is better than entropy change criteria because the former requires free energy change of system only whereas the latter requires entropy change of system and surroundings. G>0 ; the reaction is non-spontaneous and endergonic G < 0 ; the reaction is spontaneous and exergonic G=0 ; reaction is at equilibrium