To calculate the standard enthalpy change for the reaction, we first need to determine the heat released or absorbed during the reaction q . We can do this using the formula:q = mcTwhere m is the mass of the solution, c is the specific heat capacity, and T is the temperature change.First, let's find the mass of the solution. Since the density of water is approximately 1 g/mL, we can assume that the density of the solution is also approximately 1 g/mL. Therefore, the mass of the solution is:m = 50.0 mL HCl + 50.0 mL NaOH * 1 g/mL = 100.0 gNow, we can calculate the heat released or absorbed during the reaction:q = 100.0 g * 4.18 J/ gK * 10.0 C = 4180 JNext, we need to determine the moles of the limiting reactant. Since both HCl and NaOH have the same concentration and volume, they will react in a 1:1 ratio. Therefore, we can calculate the moles of either reactant:moles = 0.100 mol/L * 0.050 L = 0.005 molFinally, we can calculate the standard enthalpy change for the reaction H by dividing the heat released or absorbed by the moles of the limiting reactant:H = q / moles = 4180 J / 0.005 mol = 836000 J/molThe standard enthalpy change for the reaction between 50.0 mL of 0.100 M HCl aq and 50.0 mL of 0.100 M NaOH aq at 25 C is approximately 836 kJ/mol.