The standard enthalpy change for the neutralization of hydrochloric acid HCl with sodium hydroxide NaOH to form sodium chloride NaCl and water H2O can be determined using the following balanced chemical equation:HCl aq + NaOH aq NaCl aq + H2O l The standard enthalpy change for this reaction, also known as the enthalpy of neutralization, is approximately -57.32 kJ/mol. This value represents the amount of heat released when one mole of HCl reacts with one mole of NaOH under standard conditions 25C and 1 atm pressure .