Question

Which of the following statements is incorrect?

• A. The elements having large negative values of electron gain enthalpy generally act as strong oxidising agents
• B. The elements having low values of ionisation enthalpy act as strong reducing agents
• C. The formation of $S^{2-}\left(g\right)$ from $S\left(g\right)$ is an exothermic process
• D. Larger is the magnitude of electron gain enthalpy, easier is the formation of anion

Answer 1

The correct option is C The formation of $S^{2-}\left(g\right)$ from $S\left(g\right)$ is an exothermic process

(a) The elements having large negative values of electron gain enthalpy generally act as strong oxidising agents because they have a high tendency of accepting electrons.

(b) The elements having low value of ionisation enthalpy act as strong reducing agents because they have a high tendency of losing electrons.

(c) The formation of $S^{2-}\left(g\right)$ from $S\left(g\right)$ is an endothermic process. The incoming electron will experience inter-electronic repulsions because of which the electron gain enthalpy becomes positive.
$({\Delta }_{eg}{H}_1=\text{small negative value},{\Delta }_{eg}{H}_2=\text{large positive value})$.
So, option(c) is incorrect.

(d) Electron gain enthalpy is a measure of the ease with which an atom receives the additional electron in its valence shell in isolated gaseous phase. So, larger is the value of electron gain enthalpy, easier is the formation of anion.