The first \(\left(\Delta_i H_1ight)\) and second \(\left(\Delta_i H_2ight)\) ionisation enthalpies (in…
The first \(\left(\Delta_i H_1ight)\) and second \(\left(\Delta_i H_2ight)\) ionisation enthalpies (in \(\mathrm{kJ} \mathrm{mol}^{-1}\)) and the \(\left(\Delta_{e g} Hight)\) electron gain enthalpy (in \(\mathrm{kJ} \mathrm{mol}^{-1}\)) of the elements I, II, III, IV and \(\mathrm{V}\) are given below. From the data given in table, tell which element is the most reactive metal and the least reactive non-metal respectively?
\(\begin{array}{|l|l|l|l|}
\hline \text { Element } & \Delta_i H_1 & \Delta_i H_2 & \Delta_{e g} H \\
\hline \text { I } & 520 & 7300 & -60 \\
\hline \text { II } & 419 & 3051 & -48 \\
\hline \text { III } & 1681 & 3374 & -328 \\
\hline \text { IV } & 1008 & 1846 & -295 \\
\hline \text { V } & 2372 & 5251 & +48 \\
\hline
\end{array}\)
I and V
V and II
II and V
IV and V
Solution
I represents Li, II represents K, III represents Br, IV represents I, V represents He. So, amongst these, II represents most reactive metal and V represents least reactive non-metal. Also, II has the lowest value of first ionization enthalpy and V has positive electron gain enthalpy.
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