By titration, it is found that 65.5 mL of 0.117 M NaOH (aq) is needed to neutralize 25.0 mL of HCl (aq). Calculate the concentration of the HCl solution.

0.30 M

Explanation:

In case of titration, the following formula can be used -

M₁V₁ = M₂V₂

where,

M₁ = concentration of acid,

V₁ = volume of acid,

M₂ = concentration of base,

V₂ = volume of base.

from, the question,

M₁ = ? M

V₁ = 25.0 mL

M₂ = 0.117 M

V₂ = 65.5 mL

Using the above formula, the molarity of acid, can be calculated as,

M₁V₁ = M₂V₂

Putting the respective values -

M₁ * 25.0mL = 0.117 M * 65.5 mL

M₁ = 0.30 M