The molar concentration of the HCl is 0.67 mol/L.
1. Write the balanced chemical equation.
HCl + NaOH ⟶ NaCl + H₂O
2. Calculate the moles of NaOH
[tex]\text{Moles of NaOH} =\text{10 mL NaOH} \times \frac{\text{1 mmol NaOH}}{\text{1 mL NaOH}} = \text{10 mmol NaOH}\\[/tex]
2. Calculate the moles of HCl.
[tex]\text{Moles of HCl} =\text{10 mmol NaOH} \times \frac{\text{1 mmol HCl}}{\text{1 mol NaOH}} = \text{10 mmol HCl}\\[/tex]
3. Calculate the molar concentration of the HCl
[tex]c = \frac{\text{moles}}{\text{litres}} = \frac{\text{10 mmol}}{\text{15 mL}} = \textbf{0.67 mol/L}\\[/tex]
