Question

Energy required to dissociate $4\, g$ of gaseous hydrogen in to free gaseous atoms is $208\, k \,c a l$ at $25^{\circ} C$. The bond energy of $H-H$ bond will be:

• A. 104 k cal
• B. 104 k cal
• C. 10.4 k cal
• D. 1040 k cal

Answer 1

Answer: (A)

$2 H_{2} \rightarrow 4 H$
$\Delta H=208 \,k\, c a l$
$H-H \rightarrow 2 H ;$
$\Delta H=\frac{208}{2}=104 \,k\, c a l$