ΔH for neutralization reaction

[s3a]

The following is the question as well as the answer:

Question:
http://img29.imageshack.us/img29/304/questionkyj.jpg

Answer:
http://img29.imageshack.us/img29/426/answer.jpg

I do not understand why the final answer is negative nor why I can use the amount of NaOH to directly compare in a proportion with the ΔH of the the combination of both NaOH and HCl combined.

Any help would be greatly appreciated!
Thanks in advance!

[werehk]

Delta H is the enthalpy change of reaction. It is defined by the energy of product minus energy of reactant. So when the reaction is exothermic, the value is negative

Secondly, H+ and OH- reacts in 1 to 1 ratio