Answer:
Option b, The change in free energy of the reaction (ΔG)
Explanation:
Gibbs free energy is a measure of amount of usable energy in the system.
It is related with enthalpy (H), entropy (S) and temprature (T) as:
G = H - TS
The Gibbs free energy change (ΔG) provide spontaneity of a chemical reaction.
If ΔG is negative, then reaction is spontaneous that means reaction is moving towards forward direction.
If ΔG is positive, then reaction is non-spontaneous that means reaction is moving in backward direction.
If ΔG is zero, then reaction is at equilibrium.
Change in enthalpy only gives informtion about heat involed in a chemical reaction, it does not give information about direction of the reaction.
So, among the given options, option b is correct.
