Question

Heat evolved in the reaction $H_2+{Cl}_2⟶2HCl$ is 182 kJ. Bond energies pf H-H and Cl-Cl are 430 and 242 KJ/mol respectively. The H-Cl bond energy is:

• A. $245kJ{mol}^{-1}$
• B. $247kJ{mol}^{-1}$
• C. $336kJ{mol}^{-1}$
• D. $154kJ{mol}^{-1}$

Answer 1

The correct option is A $245kJ{mol}^{-1}$

Let bond energy of $H-Cl$ is ${}^{\prime }{x}^{\prime }$:

Total energy, $182KJ=430+242-2x2x=672-1822x=490x=245$

$\therefore H-Cl$ bond energy is $245KJ/mol$.