If its enthalpy of formation of HCl then answer should be 245.. See, enthalpy of formation is difference is enthalpy when 1 mol of product is formed from constituent elements in their natural state. Another way to write this is Final bond energy - Initial Bond energy..

But I think I've confused the sign for bond energies.. Because the bond which has more energy should be on the side where Delta H is negative.. So yes, answer should be 425.. Jo original equation tha, uske LHS pe -ve signs laga do har jagah..