To calculate the standard enthalpy change for the dissolution of 2.5 moles of sodium chloride in water, we need to know the enthalpy change of the dissolution process. Unfortunately, the given information is not sufficient to directly calculate the enthalpy change for the dissolution of NaCl.However, I can guide you on how to approach the problem if you have the necessary information.The dissolution of sodium chloride in water can be represented by the following equation:NaCl s Na aq + Cl aq The standard enthalpy change for this process H_dissolution can be calculated using the following equation:H_dissolution = H_f products - H_f reactants Where H_f products is the sum of the standard enthalpies of formation of the products, and H_f reactants is the sum of the standard enthalpies of formation of the reactants.In this case, you are given the standard enthalpy of formation of NaCl -411.1 kJ/mol , but you need the standard enthalpies of formation for Na aq and Cl aq to complete the calculation.Once you have the standard enthalpy change for the dissolution of NaCl, you can calculate the enthalpy change for dissolving 2.5 moles of NaCl using the following equation:H_total = H_dissolution * moles of NaClH_total = H_dissolution * 2.5This will give you the standard enthalpy change for the dissolution of 2.5 moles of sodium chloride in water at 25C.