Question

What is the indicator used for the titration between oxalic acid and sodium hydroxide? Justify your answer with suitable reason.

Answer 1

Hint: Indicator is a substance that changes color in response to a chemical change. Further, titration is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte. A reagent, termed as the titrant or titrator is prepared as a standard solution of known concentration and volume.

Complete step by step answer:
Titration is an important technique in the field of analytical chemistry and is sometimes referred to as volumetric analysis. It is basically a concept of stoichiometry applied to find the unknown concentration of a solution.
We have been given oxalic acid and sodium hydroxide .Now, oxalic acid is a weak organic acid and sodium hydroxide is a strong base. So, for the titration between oxalic acid and sodium hydroxide, we use phenolphthalein as an indicator. It further changes the color in a pH range of titration ($8.3 - 10.0$). As an indicator it turns pink in alkaline and is colorless in acidic solutions.

Now, let’s discuss some properties of this indicator. It is a colorless, weak acid that is widely used as an indicator. The end point is indicated by the formation of pink color since this compound dissociates to form pink anions when dissolved in water.

Note:
Oxalic acid is a dicarboxylic acid found in many vegetables and plants. It is used in the dyeing process as a mordant, in removing rust, in removing food and ink stains and many more whereas sodium hydroxide is a white crystalline solid used in the production of soaps and various other chemicals. It is also used in the textile industry and in the making of glass.