Question

The energy required to dissociate $4$ g of gaseous $H_2$ into free gaseous atoms is $872$ kJ at ${25}^o$C. The bond energy of $H-H$ bond will be :

• A. $8.72$ kJ
• B. $4.36$ kJ
• C. $436$ kJ
• D. $43.6$ kJ

Answer 1

The correct option is C $436$ kJ

As we know the energy required to dissociate $4$ g of gaseous $H_2$ into free gaseous atoms is $872$ kJ at ${25}^o$C.

So the number of moles n = $\frac{givenmassof{H}_2}{molarmassof{H}_2}$

For 4 g = 2 mole of $H_2$ E = 872 kJ

As we know for 2 mole of $H_2$ E = 872kJ

For 1 mole, bond energy of H - H will be $\frac{872}{2}$ = 436 kJ

Hence, the correct option is C.