Sodium Hydroxide (NaOH) has the ability to absorb water and CO₂ from the atmosphere. Because of this property it is impossible to prepare a standard solution form a known weight of NaOH dissolved in a definite volume of water. To accurately determine the concentration of an NaOH solution, the solution of NaOH is titrated against a known weight of a primary standard. Potassium hydrogen phthalate (KHP) is used as the primary standard in this experiment.

In this experiment you will prepare and determine the concentration (Molarity) of NaOH solution. Next you will use your NaOH solution to determine the Molecular Weight of an Unknown Acid.