Question

Compound 'X' is prepared commercially by the electrolysis of brine solution. Which of the following is not the use of 'X'?

• A. Manufacture of paper
• B. Petroleum refining
• C. Antichlor
• D. Mercirising cotton fabrics

Hint:

- Electrolysis of brine (aqueous NaCl solution) produces NaOH, Cl\(_2\), and H\(_2\). Compound 'X' here refers to NaOH. - Common uses of NaOH (Caustic Soda): - Pulp and paper industry. - Soap and detergent manufacturing. - Petroleum refining (removing acidic impurities). - Rayon (Viscose) manufacturing. - Mercerization of cotton. - Bauxite processing (Bayer process for Alumina). - Antichlor agents are used to neutralize or remove residual chlorine, e.g., sodium thiosulfate.

Answer 1

The Correct Option is C

Compound 'X' prepared by the electrolysis of brine (concentrated NaCl solution) is Sodium Hydroxide (NaOH).
The overall reaction is \( 2\text{NaCl(aq)} + 2\text{H}_2\text{O(l)} \xrightarrow{\text{electrolysis}} 2\text{NaOH(aq)} + \text{Cl}_2\text{(g)} + \text{H}_2\text{(g)} \).
So, X is NaOH.
Now let's examine the uses: 1.
Manufacture of paper: NaOH is used in the pulping process to break down wood fibers (Kraft process).
This is a use of NaOH.
2.
Petroleum refining: NaOH is used to remove acidic impurities (like sulfur compounds, phenols) from petroleum products.
This is a use of NaOH.
3.
Antichlor: An antichlor is a substance used to remove excess chlorine after bleaching, typically in the textile or paper industry.
Common antichlors are sodium thiosulfate (Na\(_2\)S\(_2\)O\(_3\)), sulfur dioxide (SO\(_2\)), sodium bisulfite (NaHSO\(_3\)).
NaOH is a strong base and is not used as an antichlor; in fact, it reacts with chlorine but not in the typical antichlor role for removing excess already used chlorine in that context.
While NaOH can react with Cl\(_2\) (e.
g.
, to form NaClO and NaCl), its primary function here is not "antichlor".
4.
Mercerising cotton fabrics: Mercerization is a treatment for cotton fabric/yarn with a caustic soda (NaOH) solution to improve its luster, strength, and dye affinity.
This is a use of NaOH.
Therefore, "Antichlor" is not a typical use of NaOH (Compound X).
This matches option (3).