A 50.00 mL sample of HCl needs 35.23 mL of 0.250 M NaOH to reach the end point. What is the HCl molarity?

1. The titration reaction is HCl + NaOH giving NaCl + H2O, a 1 to 1 mole ratio. 2. Moles of NaOH used equal 0.03523 L times 0.250 mol/L, which is 8.8075 times ten to the minus three mol. 3. The 1 to 1 ratio means the same molar amount of HCl was present in the sample. 4. The sample volume is 50.00 mL, that is 0.05000 L. 5. Molarity equals moles divided by litres: 8.8075 times ten to the minus three divided by 0.05000. 6. That gives 0.1762 mol/L, reported as 0.176 M. 7. Quoting 0.250 M simply repeats the titrant concentration and ignores the volumes entirely. _Source: OpenStax Chemistry (CC BY 4.0), Ch 4 "Stoichiometry of Chemical Reactions", section 4.5 Quantitative Chemical Analysis_