AP Chemistry. PLEASE HELP

Question

Standardization of NaOH: A primary standard called potassium hydrogen phthalate (KHP) is used to determine the exact molarity of a solution of base. KHP is a monoprotic weak acid (Molar Mass = 204.22). In one example, 0.4977 g of KHP is dissolved in 100.0 mL of water. This solution requires 14.86 mL of a solution of NaOH to neutralize it. What is the molarity of the NaOH solution? *

Answer 1

Hi Andrew I.,

I'll sketch the route to the answer.

First, find the number of moles of KHP involved = mass/molar_mass

Since each molecule of KHP (why don't you look up its structure, while you're at it?) furnishes one H+ ion, and for a monoprotic acid and mono-hydroxy base (as NaOH is) there must be equal numbers of H+ and OH- supplied, that's the same number of moles of NaOH.

Second, apply that #moles = mass / molar_mass for the NaOH.

Last, use that #moles, and the volume of the NaOH titrant used (remember to convert to L), to find its concentration in moles/L.

Can you handle it from there?