In the manufacture of sodium hydroxide by product obtained is

Options

A. `O_(2)`
B. `Cl_(2)`
C. `Na_(2)CO_(3)`
D. `NaCl`

Answer

To solve the question regarding the by-product obtained in the manufacture of sodium hydroxide (NaOH), we can follow these steps:

### Step 1: Understand the Process of Sodium Hydroxide Manufacture
The primary method for manufacturing sodium hydroxide is through the electrolysis of brine, which is a concentrated solution of sodium chloride (NaCl) in water.

**Hint:** Research the electrolysis process and its significance in producing sodium hydroxide.

### Step 2: Identify the Reaction
During the electrolysis of brine, the following reactions occur:
- 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⁻), which combine with sodium ions (Na⁺) from the brine to form sodium hydroxide (NaOH).

**Hint:** Look for the half-reactions that occur at the anode and cathode during electrolysis.

### Step 3: Write the Overall Reaction
The overall reaction for the electrolysis of brine can be summarized as:
\[ 2 \text{NaCl} + 2 \text{H}_2\text{O} \rightarrow 2 \text{NaOH} + \text{Cl}_2 + \text{H}_2 \]

From this reaction, it is clear that chlorine gas (Cl₂) is produced as a by-product along with sodium hydroxide (NaOH).

**Hint:** Summarize the products formed from the electrolysis of brine.

### Step 4: Conclusion
The by-product obtained in the manufacture of sodium hydroxide through the electrolysis of brine is chlorine gas (Cl₂).

**Final Answer:** In the manufacture of sodium hydroxide, the by-product obtained is Cl₂ (chlorine gas).

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