Question

I) Melting is an exothermic process.
II) Heat energy will cause covalent bonds in water to break as water converts from the solid state to the liquid state.
(A) Statement I is true, Statement II is true.
(B) Statement I is true, Statement II is false.
(C) Statement I is false, Statement II is true
(D) Statement I is false, Statement II is false.

Answer 1

Hint: Melting consists of a phase change reaction. It is the conversion of solid state into liquid state. Ice is a solid substance and consists of closely packed molecules. We require some amount of energy whether it is absorbed or evolved for the phase change reaction.

Complete step by step answer:
> Melting is a type of physical process, that leads to the phase change of a substance from a solid state to liquid state. This change occurs when we apply some heat or pressure to the substance and the temperature increases.
> There are two types of processes, one is exothermic, and other one is endothermic.
In the exothermic process there is release of heat leading to the rise of temperature in the surroundings. For example, the combustion process is like the lightning of a candle. In the endothermic process there is absorbance of heat leading to the cooling in the surroundings. For example, melting ice.
> Melting of ice is an endothermic process. Ice requires some heat energy to melt as absorbance of heat will lead to the breakage of bonds.
> When the melting point is attained, ions or molecules in the solid state break down and molecules become loosely packed.
Thus heat energy causes bond breakage, and the solid state is converted to the liquid state
Therefore, the correct answer is option (C) Statement I is false, Statement II is true.

Note: Endothermic and exothermic are two different processes. In the endothermic process heat energy is absorbed whereas in exothermic heat energy is evolved. Thus don’t confuse between these two processes.