Answer: Reaction 2 is a spontaneous one.
Explanation:
According to our understanding:
= +ve, meaning the reaction is non-spontaneous
= -ve, indicating the reaction is spontaneous
= 0, stating that the reaction is at equilibrium
For a reaction to be classified as spontaneous, the Gibbs free energy must yield a negative value.
Reaction 1:
Glucose + Pi ⟶ glucose-6-phosphate + H₂O, ΔG = +13.8 kJ/mol
Reaction 2:
ATP + H₂O ⟶ ADP + Pi, ΔG = -30.5 kJ/mol
From this, we can conclude that ΔG being negative indicates that reaction 2 is indeed spontaneous.