The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated as KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 g/mol. In the titration, 58.98 mL of the sodium hydroxide solution was required to react with 0.4000 g KHP. Calculate the molarity of the sodium hydroxide.

The molarity of the sodium hydroxide is 0.0332 M

Explanation:

KHP contains only one hydrogen, one mole of KHC₈H₄O₄ can be titrated with one mole of NaOH.

No. of moles of KHC₈H₄O₄ = mass / molar mass = 0.4000 / 204.22

= 1.96 x 10⁻³ moles

∴ 1.96 x 10⁻³ moles of KPH can titrate 1.96 x 10⁻³ moles of NaOH

conc of NaOH = moles x (1/volume)

                        = 1.96 x 10⁻³ (1/0.05898)

       [NaOH]    = 0.0332 M