Question

The melting point of solid substances is directly proportional to pressure acting on them. However, ice-melts at a temperature lower than its usual melting point, when the pressure increases. This is because :
A. Ice is not a true solid
B. The bonds break under pressure
C. Ice is less dense than water
D. Pressure generates heat

Answer 1

Hint:In the given question firstly we have to define the facts regarding the melting point and the basic definition. Now regarding the phenomenon we get that With an imminent increase in the value of pressure, we get that the melting point of ice will gradually decrease (i.e. ice melt) due to the less density of ice than that of water.

Complete answer:The given question statement asks about that which among the given options correctly proves the reason behind ice-melts at a temperature lower than its usual melting point, when the pressure increases.About the melting point we can say that it is the point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. It is observed that at the melting point the solid and liquid phase exist in constant equilibrium. Generally The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or \[100{\text{ }}kPa\] .With an imminent increase in the value of pressure, we get that the melting point of ice will gradually decrease (i.e. ice melt) due to the less density of ice than that of water. The phenomenon which is concluded above is called regelation and is commonly used in ice-skating.Therefore by the given facts we get that the correct option is the one which states that the ice is lighter than water.

So the correct option would be option C, Ice is less dense than water.

Note:Many laboratory techniques are used for the determination of melting points. A Kofler bench is a metal strip with temperature divisions (range from room temperature to \[300{\text{ }}^\circ C\] ). Any substance can be placed on the section of the strip, which shows its thermal behaviour at the temperature at that point. Differential scanning calorimetry tells about melting point together with its enthalpy of fusion.