Question

A solution of NaOH was standardized using solid KHP (fw = 204.32 g/mol) as the primary standard. (See Background section.) A sample of KHP weighing 0.9521 g was dissolved in water. The titration required 10.08 mL of NaOH to reach an endpoint. Calculate the concentration of the NaOH solution. (KHP and NaOH react in a 1:1 mole ratio.)

Answer 1

The molar concentration of the NaOH solution is calculated by determining the moles of titrant (NaOH) and dividing by the volume of NaOH solution in liters. For the provided data, the concentration of NaOH is 0.462 M.

Step-by-step explanation:

To calculate the concentration of the NaOH solution used to titrate a sample of KHP, we follow these steps:

1. First, determine the number of moles of KHP that were used in the titration by using the formula: moles = mass (g) / molar mass (g/mol).
2. Since the reaction between KHP and NaOH is a 1:1 mole ratio, the moles of NaOH will be equal to the moles of KHP.
3. Finally, calculate the concentration of the NaOH solution using the formula Molarity (M) = moles / volume (L), where the volume is converted from mL to L.

Following these steps for the given problem:

1. Moles of KHP = 0.9521 g / 204.32 g/mol = 0.00466 moles.
2. Moles of NaOH = 0.00466 moles (from the 1:1 ratio).
3. Volume of NaOH solution = 10.08 mL = 0.01008 L.
4. The molar concentration of NaOH = 0.00466 moles / 0.01008 L = 0.462 M.