MHT CET202526 Apr 2025Evening ShiftChemistryThermodynamics (C)Actual
Identify from following the correct set of thermodynamic conditions for the reaction to be spontaneous at all temperature.
Options
- AH >0 and S >0
- BH < 0 and S < 0
- CH 0
- DH>0 and S < 0
Correct answer
C. H 0
Step-by-step solution
The spontaneity of a reaction is determined by the sign of the Gibbs free energy change, given by G = H - T S , where G For a reaction to be spontaneous at all temperatures, both terms must contribute negatively to G . When H 0 , the equation becomes G = ( negative ) - T( positive ) . Since -T S is always negative under these conditions, G remains negative regardless of temperature. In contrast, other combinations show temperature dependence or constant non-spontaneity: H > 0 , S > 0 : spontaneous only at high temp