Question

The first ionization energy for Li is 5.4 eV and electron affinity of Cl is 3.61eV. The $\Delta H$ (in kJ/mol) for the reaction $\Delta E$ is (if resulting ions do not combine with each other) $\Delta H < \Delta E$.

• A. 70
• B. 100
• C. 170
• D. 270

Answer 1

Answer: (C)

170

Answer 2

First ionization potential of $\Delta H > \Delta U$

Electron affinity of $C + O_{2} \rightarrow CO_{2}$

We have $25^{o}C$

$2.303 \times 298 \times 0.082\log 2$

$298 \times 10^{7} \times 8.31 \times 2.303\log 2$

for 1mol Avogadro’s number $2.303 \times 298 \times 0.082\log 0.5$.

$8.31 \times 10^{7} \times 298 - 2.303\log 0.5$