Question

A chemistry student needs to determine the concentration of NaOH in a 250 mL solution. They know that 10 mL of the solution was titrated with 0.1 M HCl solution, which required 8.5 mL of the HCl solution to be fully neutralized. Based on this information, what is the concentration of NaOH in the solution?

Answer 1

To determine the concentration of NaOH in the solution, we can use the concept of titration and the balanced chemical equation for the reaction between NaOH and HCl:NaOH + HCl  NaCl + H2OFrom the balanced equation, we can see that the mole ratio between NaOH and HCl is 1:1. First, we need to find the moles of HCl used in the titration:moles of HCl =  volume of HCl    concentration of HCl moles of HCl =  8.5 mL    0.1 M moles of HCl = 0.85 mmolSince the mole ratio between NaOH and HCl is 1:1, the moles of NaOH in the 10 mL aliquot of the solution are also 0.85 mmol.Now, we can find the concentration of NaOH in the 10 mL aliquot:concentration of NaOH =  moles of NaOH  /  volume of NaOH concentration of NaOH =  0.85 mmol  /  10 mL concentration of NaOH = 0.085 MFinally, we can find the concentration of NaOH in the original 250 mL solution. Since the 10 mL aliquot was taken from the 250 mL solution, the concentration of NaOH in the original solution is the same as in the 10 mL aliquot:concentration of NaOH in the 250 mL solution = 0.085 MSo, the concentration of NaOH in the 250 mL solution is 0.085 M.