Answer:
The change from 1mol NaCl(s) → 1mol NaCl(l) illustrates the molar heat of fusion and an endothermic reaction. (Option B)
Step-by-step explanation:
Note that in this case there is a change of state from solid NaCl to liquid NaCl.
Latent heat is the energy required by an amount of substance to change state. When this change consists of moving from solid to liquid phase, this heat is called heat of fusion. In other words, the latent heat of fusion of a substance is the amount of heat that it requires to change its state from solid to liquid without varying its temperature.
A chemical reaction is endothermic when it absorbs energy from the environment, that is, heat is transferred from outside to inside the system. An exothermic reaction is one where energy is released from the system into the environment in the form of heat.
Fusion is an endothermic process. In a solid the particles are very close. By the action of heat, that is to say heat absorption, the vibration of the particles increases until they leave their fixed position. Then they move freely from each other. In this way the molecular attraction is broken and the solid enters the liquid state.
Then, The change from 1mol NaCl(s) → 1mol NaCl(l) illustrates the molar heat of fusion and an endothermic reaction. (Option B)