The standard enthalpy change of neutralization for the reaction between hydrochloric acid HCl and sodium hydroxide NaOH is given as -57.1 kJ/mol. This value represents the amount of heat released when 1 mole of HCl reacts with 1 mole of NaOH to form 1 mole of water and 1 mole of sodium chloride NaCl under standard conditions.The balanced chemical equation for this reaction is:HCl aq + NaOH aq H2O l + NaCl aq Since the heat of reaction is given for the neutralization of 1 mole of HCl and 1 mole of NaOH, the standard enthalpy change of neutralization for this reaction is -57.1 kJ/mol.