Uses of Oxalic Acid: Overview, Questions, Preparation

Oxalic acid is an organic compound found in many vegetables and plants. It is the simplest distilled solution of HOOC-COOH dicarboxylic acid, which has an acid hardness higher than acetic acid. Oxalic acid has a composition of two polymorphs and, when dissolved in water, acts as a white crystalline solid that becomes a colourless solution. It is a reducing agent, and the oxalic acid conjugate base is used as a chelating agent with oxalate.

The oxalic acid molar mass is 126 grams per mole. Since this compound's chemical formula can be COOH-COOH, oxalic acid can be understood as a dibasic acid that can donate two H+ ions.

Oxalic acid is prepared by oxidising carbohydrates like sucrose with concentrated nitric acid. The carbon atoms are broken off in pairs during oxidation, providing oxalic acid.

• Cleaning services

Oxalic acid is used for cleaning purposes or for bleaching, particularly for removing rust (iron complexing agent).

• Metallurgy extraction

An important reagent in chemistry (lanthanide) is oxalic acid. Hydrated lanthanide oxalates form in a heavily crystalline, easily filtered form, in strongly acidic solutions. They are by and large free of non-lanthanide element contamination. 

1. Beekeepers use oxalic acid as a miticide to fight the parasitic varroa mite.
2. For minerals, oxalic acid is used to clean them.
3. In some tooth-whitening products, oxalic acid is an ingredient.

Class 12 has in it one specific whole chapter dedicated to Uses of Oxalic Acids, Aldehydes, Ketones, and Carboxylic Acids. Here you will understand in detail its oxalic compounds and the different products of the reaction of oxalic compounds with different other compounds.

1. How will you prepare a 0.1 M oxalic acid solution?

Answer: Oxalic acid has a molecular mass of 126. 12.6 g of oxalic acid per litre of a solution should be dissolved to prepare the M/10 oxalic acid solution. As an alternative, 12.6 / 4 = 3.15g of oxalic acid crystals dissolve in water and produce exactly 250 ml of the solution.

2. When KMnO4 solution is added to the solution of oxalic acid, the decolourisation is sluggish at the beginning. Why, after some time, does it become instantaneous?

Answer: KMnO4 is a reactant that forms Mn2+ in the reaction, acting as an auto-catalyst. The reaction is initially slow because MnO4-is converted to Mn2+, but because of the catalytic action, once Mn2+ forms, the reaction becomes quicker.

3. Why is calcium absorption low in spinach?

Answer: Spinach is high in oxalic acid, but calcium absorption is reduced because of the presence of oxalate.

Q: Is oxalic acid polar or non-polar?

Q: What pH does oxalic acid have?

Q: For what reason is oxalic acid used?

Q: What is the oxalic acid formula?

Q: Why is dibasic acid referred to as oxalic acid?