To calculate the volume of 0.2 M hydrochloric acid HCl required to completely neutralize 25 mL of 0.1 M sodium hydroxide NaOH solution, we can use the concept of moles and the balanced chemical equation for the reaction:NaOH + HCl NaCl + H2OFrom the balanced equation, we can see that 1 mole of NaOH reacts with 1 mole of HCl. First, we need to find the moles of NaOH in the 25 mL solution:moles of NaOH = Molarity Volumemoles of NaOH = 0.1 M 0.025 L since 25 mL = 0.025 L moles of NaOH = 0.0025 molesSince 1 mole of NaOH reacts with 1 mole of HCl, we need 0.0025 moles of HCl to neutralize the NaOH.Now, we can find the volume of 0.2 M HCl required:Volume of HCl = moles of HCl / Molarity of HClVolume of HCl = 0.0025 moles / 0.2 MVolume of HCl = 0.0125 LTo convert the volume to milliliters:Volume of HCl = 0.0125 L 1000 mL/LVolume of HCl = 12.5 mLSo, 12.5 mL of 0.2 M hydrochloric acid is required to completely neutralize 25 mL of 0.1 M sodium hydroxide solution.