For the reaction $Cl_{(g)} + e^- \to Cl^-_{(g)}$,the value of $\Delta H$ is ...........

Which of the following represents the correct order of electron gain enthalpy (electron affinity) for halogens?

The correct order of electron affinity is:

The increasing order of electron affinity for the given electronic configurations of elements is:
$I. 1s^2 2s^2 2p^6 3s^2 3p^5$
$II. 1s^2 2s^2 2p^3$
$III. 1s^2 2s^2 2p^5$
$IV. 1s^2 2s^2 2p^6 3s^1$

Electronic configurations of four elements $A, B, C$ and $D$ are given below :
$(A)$ $1s^2 2s^2 2p^6$
$(B)$ $1s^2 2s^2 2p^4$
$(C)$ $1s^2 2s^2 2p^6 3s^1$
$(D)$ $1s^2 2s^2 2p^5$
Which of the following is the correct order of increasing tendency to gain electron :

The electron affinity of chlorine is $3.7 \ eV$. $1 \ g$ of chlorine is completely converted to $Cl^-$ ion in a gaseous state. $(1 \ eV = 23.06 \ kcal \ mol^{-1})$. Energy released in the process is $...... \ kcal$.