To calculate the standard enthalpy change for the reaction, we first need to determine the amount of heat released or absorbed during the reaction. We can do this by using the heat capacity formula:q = mcTwhere q is the heat released or absorbed, m is the mass of the solution, c is the specific heat capacity, and T is the change in temperature.First, let's find the moles of HCl and NaOH in the solution:moles of HCl = volume concentration = 50 mL 0.1 M = 5 mmolmoles of NaOH = volume concentration = 50 mL 0.1 M = 5 mmolSince the balanced equation shows a 1:1 ratio between HCl and NaOH, the reaction will go to completion, and we will have 5 mmol of NaCl and 5 mmol of H2O formed.Next, we need to find the mass of the solution. Assuming the density of the solution is approximately equal to the density of water 1 g/mL , we can calculate the mass as follows:mass of solution = volume density = 50 mL HCl + 50 mL NaOH 1 g/mL = 100 gNow, we need to find the change in temperature T . Since the problem does not provide the initial and final temperatures, we cannot calculate T directly. However, we can still find the standard enthalpy change H using the heat capacity formula:H = q / moles of reactionWe know the specific heat capacity c is 4.18 J/g K, and we have the mass of the solution m and the moles of reaction. We can rearrange the heat capacity formula to solve for T:T = q / mc Now, we can substitute the values into the H formula:H = q / moles of reaction = mcT / moles of reactionSince we don't have the value for q, we cannot calculate the standard enthalpy change H for this reaction. We would need either the initial and final temperatures or the heat released/absorbed q to solve this problem.