Calculating Heat of Reaction: NaOH + HCl

[chem4u1]

I have trying to write a hypothesis for this reaction but boy am I lost

NaOH --> Na(+) + OH(-)
NaOH + H (+) + Cl (-) --> H20 + Na(+) + Cl(-)
NaOH +OH (-) + H(+) Cl (-) --> H20 + Na(+) + Cl(-)

Which reaction would produce the most heat and why??
How would i calculate this

Thanks

 

[Cesium]

Look up enthalpies of formations then compare- summation of the products minus the summation of the reactants. By the way, equation #3 makes no sense.

 

[chem4u1]

whoops Equation #3 shouls read
Na (+) + OH(-) + H (+) + Cl (-) --> H2O + Na (+) + Cl (-)