Chlor alkali process is used for preparation of_____

Explanation

**Step-by-Step Solution:**

1. **Understanding the Chlor-Alkali Process:**
The chlor-alkali process is an industrial method used to produce chlorine gas, hydrogen gas, and sodium hydroxide (NaOH) from the electrolysis of brine, which is a concentrated solution of sodium chloride (NaCl) in water.

2. **Components of the Process:**
- **Brine Solution:** The starting material for the chlor-alkali process is a saturated solution of sodium chloride in water, commonly referred to as brine.
- **Electrolysis:** The process involves passing an electric current through the brine solution, which causes chemical reactions to occur.

3. **Chemical Reactions:**
During the electrolysis of brine, the following reactions take place:
- At the anode (positive electrode), chloride ions (Cl⁻) are oxidized to form chlorine gas (Cl₂).
- At the cathode (negative electrode), water is reduced to form hydrogen gas (H₂) and hydroxide ions (OH⁻).
- The hydroxide ions combine with sodium ions (Na⁺) present in the brine to produce sodium hydroxide (NaOH).

4. **Products of the Chlor-Alkali Process:**
The main products obtained from the chlor-alkali process are:
- Sodium Hydroxide (NaOH)
- Chlorine Gas (Cl₂)
- Hydrogen Gas (H₂)

5. **Conclusion:**
Therefore, the chlor-alkali process is primarily used for the preparation of sodium hydroxide, along with chlorine and hydrogen gases.

**Final Answer:**
The chlor-alkali process is used for the preparation of **sodium hydroxide (NaOH)**.

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