Question

If an unknown concentration 25.00 mL HCl consumes 20 mL of 0.123 M NaOH to reach endpoint, calculate the concentration of the HCl solution (Show calculation).

Please show calculations!!

Answer 1

25.00 mL HCl consumes 20 mL of 0.123 M NaOH to reach endpoint.

• So, during titration, we know that : at ideal endpoint the solution becomes neutral due to equal quantities of acid and alkali.

So, we can say:

$V_{1}S_{1} = V_{2}S_{2}$

$\implies 25 \times S_{1} = 20 \times 0.123$

$\implies S_{1} = \dfrac{20 \times 0.123}{25}$

$\implies S_{1} \approx 0.098 \: M$

So, concentration of HCl was approximately 0.098 M.