Question

Which equation represents the first electron affinity of chlorine?

Answer 1

Answer:
            Option-A [Cl (g) + e⁻  →  Cl⁻ (g)] is the correct answer.

Explanation:
                   First electron affinity is the amount of heat evolved when an electron is added to a neutral atom.
                   Such problems often come in questions related to Born-Haber Cycle topic. Let suppose Mg and Cl₂ is reacted to form MgCl₂ crystal.

Then the Cl₂ gas is first atomized as follow,

                                        Cl₂     →     2 Cl

After atomization an electron is added to neutral chlorine atoms, as,

                                      Cl  +  e⁻    →     Cl⁻

So, option A is correct choice.