The bond dissociation energies of gaseous `H_(2), Cl_(2) and HCl` are 104, 58 and 103 kCal/mole respectively. If magnitude of heat of formation of HCl = 11x, x=?

Answer

2

Explanation

Reaction for formation of HCl is `(1)/(2) H_(2(g)) + (1)/(2) Cl_(2(g)) rarr HCl_((g))`
As all are in gaseous state
`Delta H = Sigma` B.E of Reactions `- Sigma` B.E. of products
`= (1)/(2) (104) + (1)/(2) (58) - 103 = -22`