Question

The standard Gibbs energy change for the reaction at 25 degree celsius--
H₂O--- H⁺ +. OH^{​​​​​--
the reaction is a reversible one.}

Answer 1

H2O(l)<===>H+(aq) + OH-(aq)
making use of the deltaGf* values at 25*C and substuting it
ΔG°rxn = Σ G°f (products) - Σ ΔG°f (reactants) in the formula, we get
=[deltaGf*(H+) + deltaGf*(OH-)] - [deltaGf*(H2O)]
= [0 + (-157.27656)] -[-237.178408]
=79.9KJ/mol