Which of the following is consistent with a spontaneous process in the forward direction? A) ∆Suniv >0, ∆G<0, T∆Suniv >0.
B) ∆Suniv <0, ∆G>0, T∆Suniv <0.
C) ∆Suniv >0, ∆G<0, T∆Suniv <0.
D) ∆Suniv <0, ∆G<0, T∆Suniv <0.
E) ∆Suniv >0, ∆G>0, T∆Suniv >0.

A) ∆Suniv >0, ∆G<0, T∆Suniv >0.

Explanation:

The connection between entropy and the spontaneity of a reaction is expressed by the second law of thermodynamics: The entropy of the universe increases in a spontaneous process and remains unchanged in an equilibrium process.

Mathematically, we can express the second law of thermodynamics as follows:

For a spontaneous process: ΔSuniv = ΔSsys + ΔSsurr > 0

Therefore, the second law of thermodynamics tells us that a spontaneous reaction increases the entropy of the universe; that is, ΔSuniv > 0.

If we want spontaneity expressed only in terms  of the properties of the system (ΔHsys and ΔSsys), we use the following equation:

-TΔSuniv = ΔHsys - TΔSsys < 0

That means that T∆Suniv >0.

This equation says that for a process carried out at constant pressure and temperature  T, if the changes in enthalpy and entropy of the system are such that ΔHsys - TΔSsys  is less than zero, the process must be spontaneous.

Finally, if the change in free energy is less than zero (ΔG<0), the reaction is spontaneous in the forward direction.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.