If it requires 35.0 milliliters of 0.50 molar NaOH to neutralize 25.0 milliliters of HCl, what is the concentration of the HCl solution?

Balanced equation: NaOH + HCl yields NaCl + H2O

The balanced chemical equation would be as follows:

NaOH + HCl = NaCl + H2O

We are given the volumes of the reactants used and the concentration of sodium hydroxide for the reaction. We use these values to determine first the number of moles of HCl needed for the reaction. We calculate as follows:

0.50 M NaOH (0.035 L) (1 mol HCl / 1 mol NaOH) = 0.0175 mol HCl

Molarity of HCl = 0.0175 mol HCl / 0.025 L = 0.7 M HCl