Sodium Hydroxide (Uses) MCQs Quiz | Class 10
Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. This quiz focuses on Sodium Hydroxide (NaOH), covering its production via the Chlor-alkali process, industrial applications in soap, paper, and textiles, and daily use examples. Attempt the 10 MCQs below, submit to check your score, and download the PDF solution for revision.
Overview: Sodium Hydroxide (NaOH)
Sodium Hydroxide, commonly known as Caustic Soda, is a high-utility strong base used extensively across various industries. It is chemically represented as NaOH. It is a white, translucent solid in the form of pellets or flakes and is highly soluble in water, producing a considerable amount of heat (exothermic).
1. Preparation: The Chlor-Alkali Process
Sodium hydroxide is produced industrially by the electrolysis of an aqueous solution of Sodium Chloride (called brine). This process is known as the chlor-alkali process because of the products formed: Chlor for chlorine and Alkali for sodium hydroxide.
- Anode: Chlorine gas is released.
- Cathode: Hydrogen gas is released.
- Near Cathode: Sodium hydroxide solution is formed.
2. Major Industrial Uses
The versatility of NaOH makes it crucial for several sectors:
- Soap and Detergents: It is the primary ingredient used in saponification, the process of converting fats and oils into soap.
- Paper Manufacturing: It is used to pulp wood for making paper by dissolving lignin.
- Artificial Fibres: It is essential in the production of rayon and other artificial textiles.
- Bauxite Purification: In metallurgy, it is used to purify bauxite ore from which aluminium is extracted (Bayer process).
- Degreasing Metals: It is effective in cleaning oil and grease from metal sheets and machinery parts.
3. Summary Table of Products from Chlor-Alkali Process
| Product | Key Application |
|---|---|
| Sodium Hydroxide (NaOH) | Making soaps, detergents, paper, artificial fibres. |
| Chlorine (Cl2) | Water treatment, PVC, pesticides, CFCs. |
| Hydrogen (H2) | Fuels, margarine, ammonia for fertilizers. |
4. Quick Revision List
- Common Name: Caustic Soda.
- Nature: Corrosive and Strong Base.
- Reaction with Metals: Reacts with Zinc or Aluminium to produce Hydrogen gas.
- Interaction with Chlorine: Reacts with Chlorine to produce Bleach (Calcium Hypochlorite involves lime, but NaOH + Cl2 yields Sodium Hypochlorite used in household bleach).
5. Extra Practice Questions
- What happens when NaOH reacts with Zinc metal? (Ans: Sodium Zincate and Hydrogen gas are formed.)
- Why is the process of making NaOH called chlor-alkali? (Ans: Due to formation of Chlorine and Alkali.)
- Which artificial fibre requires NaOH for its production? (Ans: Rayon.)
- Name the gas evolved at the cathode during the electrolysis of brine. (Ans: Hydrogen.)
- Is NaOH acidic or basic? (Ans: Strongly Basic.)
Content created and reviewed by the CBSE Quiz Editorial Team based on the latest NCERT textbooks and CBSE syllabus. Our goal is to help students practice concepts clearly, confidently, and exam-ready through well-structured MCQs and revision content.