Hydrochloric acid is neutralized by calcium hydroxide according to the following reaction:
Ca(OH)2 + 2 HCl (aq) → CaCl2(aq) + 2 H2O (l)
What is the concentration of a calcium hydroxide solution if 16.40 mL are exactly neutralized by 12.00 mL of 0.1440 M HCl solution? (Note: 1.0 M Ca(OH)2 = 2.0 M OH- )

The answer to your question is 0.052 M

Explanation:

Data

[Ca(OH)₂] = ?

Volume of Ca(OH)₂ = 16.4 ml

[HCl] = 0.144 M

Volume of HCl = 12 ml

Balanced chemical reaction

               Ca(OH)₂  +  2HCl  ⇒   CaCl₂  +  2 H₂O

Process

1.- Calculate the moles of HCl

Molarity = moles/volume

-Solve for moles

moles = Molarity x volume

-Substitution

moles = 0.144 x 12/1000

-Simplification

moles = 0.144 x 0.012

-Result

moles = 0.001728

2.- Calculate the moles of Ca(OH)₂

                  1 mol of Ca(OH)₂ 2 moles of HCl

                   x                           0.001728 moles of HCl

                             x = (0.001728 x 1) / 2

                             x = 0.000864 moles of Ca(OH)₂

3.- Calculate the concentration of Ca(OH)₂

Molarity = 0.000864/0.0164

-Result

Molarity = 0.052