An experiment was carried out to measure the enthalpy change of the following reaction.
NaOH(aq) + HCl(aq)
NaOH(aq) + HCl(aq) = NaCl(aq) + HOH This is an enthalpy of neutralization (ΔHn), the change in enthalpy that occurs when one equivalent of an acid and one equivalent of a base undergo a neutralization reaction to form water and a salt. It is a special case of the enthalpy of reaction. It is defined as the energy released with the formation of 1 mole of water. When a strong acid, HA, reacts with a strong base, BOH, the reaction occurs as the acid and the base are fully dissociated and neither the cation B+ nor the anion A− are involved in the neutralization reaction. The enthalpy change for this reaction is -57.62 kJ/mol at 25C. (https://en.wikipedia.org/wiki/Enthalpy_of_neutralization )