Question

Caustic soda is chemically sodium hydroxide (NaOH)
(A) True
(B) False

Answer 1

Hint: Caustic soda is a pure crystalline colourless solid. It is highly soluble in water and insoluble in non-polar solvents. It is also known by the name-lye.

Complete step by step solution:
- Caustic soda, mostly known as sodium hydroxide is an inorganic compound with chemical formula –NaOH.
- It is an ionic compound that is white in colour.
- It is also known by the name-lye.
- NaOH is bitter in taste and feels slippery with skin contact.
- NaOH is a strong alkali as it complexly dissociates into $O{{H}^{-}}$and $N{{a}^{+}}$ions in aqueous solution.
- Hence, we can conclude that the statement - Caustic soda is chemically sodium hydroxide (NaOH) is true.
- Therefore, the answer will be option (A) True.

Additional Information:
- Caustic soda is prepared by many methods. Some of them are - Castner-Kellner process, Loewig’s process and Nelson Diaphragm cell.
- NaOH is used in many industries.
- It is used in laboratories as a reagent and is also used in pH regulation.
- It is also used for pulping of wood in the process of making paper.
- It is used as a cleansing agent and is also used in the production of washing soda.
- NaOH is used during water purification to raise the pH of water supplies.
- It is used in the Bayer process for the production of aluminium.
- NaOH is dangerous and can cause chemical burns upon skin contact and may even cause permanent blindness upon contact with eyes.

Note: Caustic Soda (NaOH) is highly soluble in water. It readily absorbs moisture to form a series of hydrates. The commercially available caustic soda is the monohydrate $NaOH.{{H}_{2}}O$. This monohydrate crystallizes from water solutions at room temperature. Hence, if the question is if caustic soda is pure anhydrous NaOH, the answer will be no.