Question

During the formation of $NaCl$, which processes are endothermic?

• A. Sublimation
• B. Ionization
• C. Bond dissociation
• D. All of these

Answer 1

The correct option is D All of these

Sublimation is the phase transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. Sublimation is an endothermic process that occurs at temperatures and pressures below a substance's triple point in its phase diagram.

$Na\left(s\right)\to Na\left(g\right)$ $\Delta H_{sub}=+108kJ$

Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions, often in conjunction with other chemical changes.

$Na\left(g\right)\to N{a}^{+}\left(g\right)$ $IE=+496kJ$

Bond dissociation energy (BDE or D0) is one measure of the strength of a chemical bond. It can be defined as the standard enthalpy change when a bond is cleaved by homolysis, with reactants and products of the homolysis reaction at 0 K (absolute zero).

$\frac{1}{2}{Cl}_2\to Cl\left(g\right)$ $\Delta H_{diss}=+122kJ$

Since, $\Delta H$ is positive for all the three phenomenon they are endothermic.