If the enthalpy change for the reaction,
`CH_(4)(g)+Cl_(2)(g)toCH_(3)Cl(g)+HCl(g),DeltaH=-25`kcal,
bond energy of C-H is 20 kcal `mol^(-1)` greater than the bond energy of C-Cl and bond energies of H-H and H-Cl are same in magnitude, then for the reaction `H_(2)(g)+Cl_(2)(g)to2HCl(g),DeltaH=`?

Options

A. `-22.5kcal//mol`
B. `-20.5kcal//mol`
C. `-32.5kcal//mol`
D. `-12.5kcal//mol`

Answer

A