Question

1. Which curve or point of a phase diagram would indicate the melting point at various temperatures and pressures?

Answer 1

I think the correct answer from the choices listed above is the second option. It is the fusion curve that would indicate the melting point at various temperatures and pressures. It is the boundary in the phase diagram that separates the solid and the liquid phase. 

Answer 2

Which curve or point of a phase diagram would indicate the melting point at various temperatures and pressures?

fusion curve