If the enthalpy change for the reaction `CH_4(g)+Cl_2(g)rarrCH_3Cl(g)+HCl(g)`, `triangleH`=-25 kcal. Bond energy of C-H is 20kcal/mol 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: `1//2H_2(g)+1//2Cl_2(g)rarrHCl(g)` `triangleH` is

Options

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

Answer

A