Question

Help please?

Answer 1

all the answers are based on the assumption that during any change in phase temperature is held constant , which is visible from graph

1-- when heat content is decreased , then its freezing because molecules come together

2-- when heat content is increased , then its melting , its like giving heat to molecules and separation among them increases

3-- at further higher temperature when heat content is reduced its condensation

4-- and when heat content is increased at higher temperature its vaporisation or sometimes steam formation (there is a minor difference )

so its C