The correct option is D X = 50 oC
Y = 150 oC
Conversion of physical state on heating:
Solid melting−−−−−→ Liquid boiling−−−−−→ Gas
Conversion of physical state on cooling:
Gas condensation−−−−−−−−−−→ Liquid freezing−−−−−−→ Solid
∙ Boiling point of a substance is the temperature at which it changes its state from liquid to gas. It is same as the temperature at which it condenses (i.e. changes from gas to liquid).
∙ Since boiling point of the given substance is 150 oC, the temperature at which it condenses is 150 oC, that is, Y = 150 oC.
∙ Melting point of a substance is the temperature at which it changes its state from solid to liquid. It is same as the temperature at which it freezes.
∙ Since melting point of the given substance is 50 oC, the temperature at which it freezes is 50 oC, that is, X = 50 oC.