Energy requried to dissociate 4 g of gaseous hydrogen into free gaseous atoms is 208 kcal at `25^(@)C`. The bond energy of H-H will be

Options

A. 104 kcal `mol^(-1)`
B. 52 kcal `mol^(-1)`
C. 10.4 kcal `mol^(-1)`
D. 1040 kcal `mol^(-1)`

Answer

A

Explanation

Number of moles of hydrogen`=(4g)/(2" g "mol^(-1))=2` moles
Given, `2H_(2)(g)to4H(g),DeltaH=104` kcal `mol^(-1)`. Hence, bond energy of H-H bond is 104 kcal `mol^(-1)`