ANS:A - increases.

For a spontaneous natural process at constant temperature and pressure, the free energy of the system always decreases. This statement aligns with the Second Law of Thermodynamics, which states that for a spontaneous process occurring at constant temperature and pressure, the overall entropy of the system and its surroundings increases. The change in free energy (ΔG) for a process is related to the change in entropy (ΔS) and the change in enthalpy (ΔH) through the equation: ΔG = ΔH - TΔS At constant temperature and pressure, the change in free energy (ΔG) is related only to the change in entropy (ΔS). Since the entropy of the system and its surroundings increases for a spontaneous process, ΔS is positive. Therefore, for ΔG to be negative (indicating a spontaneous process), the enthalpy change (ΔH) must be greater than the product of temperature (T) and the change in entropy (ΔS), ensuring that ΔG is negative. In simpler terms, for a spontaneous natural process at constant temperature and pressure, the free energy of the system decreases because the increase in entropy overcomes the enthalpy contribution to the change in free energy.