Explain chlor-alkali process with chemical equation. Name the products formed at anode and cathode.
Generated by claude-sonnet-4-6 · 2026-06-15 06:42 · grounding rag
Model Answer
Chlor-Alkali Process:
When electricity is passed through an aqueous solution of sodium chloride (brine), it decomposes to give sodium hydroxide, chlorine, and hydrogen. This is called the chlor-alkali process.
$$2\text{NaCl}(aq) + 2\text{H}_2\text{O}(l) \xrightarrow{\text{electricity}} 2\text{NaOH}(aq) + \text{Cl}_2(g) + \text{H}_2(g)$$
- At Anode: Chlorine gas (Cl₂) is produced.
- At Cathode: Hydrogen gas (H₂) is produced; sodium hydroxide (NaOH) is formed near the cathode.
Source: Acids, Bases and Salts, Chapter 2
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Explanation
- The name "chlor-alkali" comes from the two main products: chlorine (chlor) and alkali (NaOH).
- Examiners expect: (1) a clear definition/description of the process, (2) the balanced chemical equation with state symbols, and (3) specific products named at each electrode.
- Remember: Cl₂ → anode; H₂ → cathode; NaOH forms near cathode. All three products must be mentioned for full marks.