Question

Enthalpy change for the reaction,
$4 H _{( g )} \rightarrow 2 H _{2( g )}$ is $-869.6\, kJ$
The dissociation energy of $H - H$ bond is

• A. - 434.8 kJ
• B. - 869.6 kJ
• C. + 434.8 kJ
• D. + 217.4 kJ

Answer 1

Answer: (C)

Given
$4H(g) \to 2H_{2}(g) ; \Delta H = - -869.6 \, kJ$
or $2H_{2} (g) \to 4H(g) ; \Delta H = 869.6\, kJ$
$H_{2} (g) \to 2H(g) ; \Delta H = \frac{869.6}{2} = 434.8\, kJ$