The heat of neutralization of $\ce{HCl~ (aq)}$ by $\ce{NaOH}$ is $\mathrm{-55.9~kJ/mol}$ $\ce{H2O}$ produced. If $\mathrm{50~ml}$ of $\mathrm{1.6~M}$ $\ce{NaOH}$ at 25.15 celsius is added to $\mathrm{25~ml}$ of $\mathrm{1.79~M}$ $\ce{HCl}$ at 26.34 celsius in a plastic foam cup calorimeter, what will be solution temperature be immediately after the neutralization reaction has occurred?
I'm always overwhelmed by the question if it provided me too much information. I don't know what equation and concept to use first. (But I know all related-equations in this unit.)
I need a detailed explanation to understand! Im not sure which one is the initial temperature? 25.15 celsius of $\ce{NaOH}$ or 26.34 celsius $\ce{HCl}$?