Final answer:
The enthalpy change for the reaction NaOH(aq) + HCl(aq) → H₂O(l) + NaCl(aq) is -56 kJ.
Step-by-step explanation:
The enthalpy change of a chemical reaction is denoted by ΔHrxn. In this case, the reaction is:
NaOH(aq) + HCl(aq) → H₂O(l) + NaCl(aq)
The enthalpy change for this reaction, ΔHrxn, is -56 kJ. Therefore, the correct answer is a. -82.5 kJ.