Gibbs free energy at phase changes

[Samantha Man 1L]

Why is Gibbs free energy change zero at phase changes, like boiling points, that are done at constant T and P? Or is that not always the case?

[Annalyn Diaz 1J]

I believe that Gibbs free energy is 0 at phase changes because there’s an equilibrium that exists during that phase change and dG =0 at equilibrium.

[Alexa_Henrie_1I]

When G=0, there is no energy free to do work.