Question

What is the concentration of a hydrochloric acid (HCl) solution in moles per liter (M) if 25 mL of a 0.1 M sodium hydroxide (NaOH) solution is required to neutralize 50 mL of the HCl solution?

Answer 1

To solve this problem, we can use the concept of stoichiometry and the balanced chemical equation for the reaction between hydrochloric acid  HCl  and sodium hydroxide  NaOH :HCl + NaOH  NaCl + H2OFrom the balanced equation, we can see that the mole ratio between HCl and NaOH is 1:1.Next, we can use the volume and concentration of the NaOH solution to find the moles of NaOH:moles of NaOH = volume  L   concentration  M moles of NaOH = 0.025 L  0.1 M = 0.0025 molesSince the mole ratio between HCl and NaOH is 1:1, the moles of HCl will also be 0.0025 moles.Now, we can use the moles of HCl and the volume of the HCl solution to find the concentration of HCl:concentration of HCl  M  = moles of HCl / volume of HCl  L concentration of HCl  M  = 0.0025 moles / 0.050 L = 0.05 MSo, the concentration of the hydrochloric acid solution is 0.05 M.