To solve this problem, we need to first determine the moles of HCl and NaOH in the solution, then find the moles of the excess reactant, and finally calculate the pH of the resulting solution.1. Calculate the moles of HCl and NaOH:Moles of HCl = Molarity Volume = 0.1 M 0.100 L = 0.010 molesMoles of NaOH = Molarity Volume = 0.05 M 0.200 L = 0.010 moles2. Determine the limiting reactant and the moles of the excess reactant:In this case, both HCl and NaOH have the same number of moles 0.010 moles , so they will completely react with each other, and there will be no excess reactant. The resulting solution will be a neutral salt solution.3. Calculate the pH of the resulting solution:Since the solution is neutral, the pH will be 7.