Q1: Which of the following is insensitive to changes in pressure ?

ANS:D - Both (b) and (c)

Both the melting point and the heat of fusion are insensitive to changes in pressure under normal conditions. The melting point of a substance is the temperature at which it changes from solid to liquid phase. This temperature remains constant as long as the pressure remains constant. Similarly, the heat of fusion is the amount of heat required to convert a unit mass of a substance from solid to liquid phase at its melting point. This quantity also remains constant regardless of pressure changes under normal conditions. However, the heat of vaporization can be sensitive to pressure changes. It is the amount of heat required to convert a unit mass of a substance from liquid to vapor phase at its boiling point. This quantity can vary with changes in pressure. Therefore, the correct answer is: Melting point and heat of fusion are both insensitive to changes in pressure.