Question

The melting point of a substance which contracts on melting, ______ when the pressure is increased.

• A. increases
• B. decreases
• C. becomes $0{}^{\circ }\text{C}$
• D. does not change

Answer 1

The correct option is B decreases

The melting point of a substance which contracts on melting (like ice) decreases by the increase in the pressure. A few substances, ice, for example, contract as they melt. An increase in pressure makes it easier for the molecules of the substance to move rapidly thereby melting it sooner. Therefore, an increase in pressure lowers the melting point.