Standardization of a sodium hydroxide (NaOH) solution involves titrating it against a standard acid solution of known concentration and purity, such as potassium hydrogen phthalate (KHP). The procedure involves dissolving a weighed sample of KHP in water, adding an indicator and titrating with NaOH until the endpoint is reached. The concentration of NaOH is then calculated using the titrated volumes and mole amount of KHP. The process should be repeated and the average concentration taken for accuracy.

1. Standerization method for sodium hydroxide solution:
Standardization of sodium hydroxide (NaOH) is a process of determining the exact
concentration of a given solution of NaOH. This is usually done by titration using a primary
standard acid, such as potassium hydrogen phthalate (KHP), which has a known purity and
can be accurately weighed. The following is a basic procedure for standardizing a NaOH
solution:
1. Weigh out a sample of KHP and dissolve it in distilled water to make a known volume of
solution.
2. Add a few drops of phenolphthalein indicator to the KHP solution.
3. Slowly add NaOH solution to the KHP solution until the endpoint is reached. The endpoint is
indicated by a permanent pink color.
4. Record the volume of NaOH solution used to reach the endpoint.
5. Calculate the concentration of the NaOH solution using the formula:
NaOH concentration (mol/L) = (mol of KHP / volume of KHP solution used for titration) x
(volume of NaOH solution used for titration)
It is important to note that the standardization process should be repeated multiple times
to ensure accuracy and precision. The average value of the concentration obtained from the
multiple trials can be taken as the true value.
References:
1. Skoog, D. A., West, D. M., & Holler, F. J. (2013). Fundamentals of analytical chemistry.
Cengage Learning.
2. Harris, D. C. (2010). Quantitative chemical analysis. Macmillan.