Question

You prepare the standard solution from 0.318 g of KHP in 250.0 ml of water. You then require 9.72 ml of NaOH solution to complete the titration. What is the concentration of the NaOH solution?

Answer 1

To find the concentration of NaOH solution, calculate the number of moles of KHP and use the stoichiometry of the chemical reaction between KHP and NaOH, which is 1:1. The concentration of NaOH solution that titrated 0.318 g of KHP in 9.72 ml is 0.1601 M.

Step-by-step explanation:

To calculate the concentration of the NaOH solution used to titrate the KHP, we first need to determine the number of moles of KHP used in the titration. Potassium hydrogen phthalate (KHP) has a molar mass of approximately 204.22 g/mol. The number of moles of KHP is calculated using the formula:

n = mass / molar mass

n(KHP) = 0.318 g / 204.22 g/mol = 0.001557 mol

The balanced chemical equation for the reaction between KHP and NaOH is:

KHC8H4O4 + NaOH → NaKC8H4O4 + H2O

From the equation, we understand that the stoichiometry between KHP and NaOH is 1:1. Therefore, 0.001557 mol of NaOH reacts with 0.001557 mol of KHP. To find the molarity of NaOH, we divide the number of moles of NaOH by the volume of the NaOH solution that was used, expressed in liters.

Molarity (M) = n(NaOH) / V(NaOH in L)

M(NaOH) = 0.001557 mol / 0.00972 L = 0.1601 M