The melting point of paraffin wax (which contracts on solidification) __________ with pressure rise.

ANS:A - increases

The melting point of paraffin wax, which contracts on solidification, typically decreases with a rise in pressure. This behavior is in line with the general principle observed for most substances: as pressure increases, the melting point decreases. This relationship is based on the Clausius–Clapeyron equation, which describes the dependence of the phase transition temperature on pressure. When pressure is increased, the molecules in the solid phase are forced closer together, which tends to counteract the thermal energy required to overcome the attractive forces and melt the substance. As a result, the melting point decreases under higher pressure conditions. Therefore, the melting point of paraffin wax is expected to decrease with a rise in pressure.