Question

Electron Affinity of Cl is 3.7 eV. How much Energy released in kCal when 2g of gaseous chlorine atoms is converted to Cl^- ions in the gaseous state.

• A. $\text{4.80 kCal}$
• B. $\text{5.20 kCal}$
• C. $\text{1.50 kCal}$
• D. $\text{3.60 kCal}$

Answer 1

Answer: (A)

Moles of Cl(g)= $\frac{2}{35 . 5}$ = $0.0563mole$
Energy Released,
$1ev/atom=96.5kJ/mole$
= $0.0563\times 3.7\times 96.5 = 20.10kJ$
= $\frac{20 .10}{4 . 184}$ = $4.80kCal$