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When water solidifies to ice then heat is:
C.No change
D.Depending on the condition of heat absorbed or liberated

Last updated date: 13th Jul 2024
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Hint: We need to know that freezing is a phase transition in which a liquid becomes a solid as its temperature falls below its freezing point. The solidification phase shift of a liquid or the liquid content of a material, normally due to cooling, is described as freezing by the international standard. The most common method of freezing liquids is crystallisation, which involves the creation of a crystalline solid from a uniform liquid. This is a first-order thermodynamic phase transition, which ensures that as long as solid and liquid coexist, the temperature of the whole device stays very close to the melting point due to sluggish heat removal when in contact with air, which is a weak heat conductor.

Complete answer:
We have to remember that freezing is almost always an exothermic operation, ensuring that heat and pressure are released as the liquid transforms into a solid. This is often misunderstood because, although the substance is supercooled, the temperature of the material does not increase after freezing. However, this is understandable because heat must be constantly separated from the frozen liquid otherwise the freezing process can come to a halt. The latent heat emitted during freezing is known as the enthalpy of fusion, and it is identical to the energy used to melt the same volume of solid. As a result, freezing is the method of turning moisture into ice.
Freezing is the method of turning a liquid into ice. The energy lost by water molecules during freezing is gained by the molecules around them. Hence energy is liberated.

Hence, the correct option is option (A).

It must be noted that while some scholars distinguish solidification from freezing as a mechanism in which a liquid solidifies by rising pressure, the two terms are often used interchangeably. The melting and freezing points of most substances are the same; however, some substances have different solid–liquid transition temperatures. The melting and freezing points of agar, for example, show hysteresis. It melts at $185^\circ C$ ($185$degrees Fahrenheit) and solidifies at $32^\circ C$ ($89.6$degrees Fahrenheit) to $40^\circ C$ ($104$degrees Fahrenheit).