Question

A 1.513 g sample of KHP (C8H5O4K) is dissolved in 50.0 mL of DI water. When the KHP solution was titrated with NaOH, 14.8 mL was required to reach the phenolphthalien end point. Calculate the molarity of the NaOH solution

Answer 1

Answer:

0.501 M

Explanation:

• KHP + NaOH → NaKP + H₂O

First we convert 1.513 g of KHP into moles, using its molar mass:

• 1.513 g ÷ 204.22 g/mol = 7.41x10⁻³ mol = 7.41 mmol

As 1 mol of KHP reacts with 1 mol of NaOH, in 14.8 mL of the NaOH solution there were 7.41 mmoles of NaOH.

With the above information in mind we can calculate the molarity of the NaOH solution:

• 7.41 mmol / 14.8 mL = 0.501 M