When I add Hydrochloric acid to Sodium hyrdroxide what do you think will happen?

Well, an exothermic reaction will occur.

When the HCL reacts with the NaOH, bonds will be broken, and energy is taken in from the surroundings to break those bonds, but when bonds are formed as new products are formed from the reactants , energy is released. As more energy is released by the formation of the bonds, then the reaction is exothermic. The temperature will increase as you add more acid until a certain point, the maximum temperature.

This will be an exothermic reaction, meaning it will release heat and feel warmer on the glass. The solution will also heat up.

If you have the same molarities of HCl and NaOH (ex: 1 M), then it will continue to heat up until you add more than 25 mL of acid.

Exothermic reaction (heat given off) and will increase the temperature.. I suggest you take the temperature of the solution before the reaction begins (of acid) and then during and after the reaction. Be careful when working with acid... it hurts x_x