An Aqueous solution of NaCl (Sodium chloride) undergoes electrolysis and formation of NaOH (Sodium Hydroxide) i.e. Caustic Soda, $Cl_{2}$ (Chlorine) and $H_{2}$ (Hydrogen) takes place. What is the name of this process.

Question

Accepted Answer

The correct option is (3):

The process described, where an aqueous solution of $\mathrm{NaCl}$ (sodium chloride) undergoes electrolysis to produce $\mathrm{NaOH}$ (sodium hydroxide or caustic soda), $\mathrm{Cl_2}$ (chlorine gas), and $\mathrm{H_2}$ (hydrogen gas), is known as the Chloralkali Process. This is a major industrial process for the production of these essential chemicals. During electrolysis, electricity is passed through the aqueous $\mathrm{NaCl}$ solution (brine). At the anode, chloride ions ($\mathrm{Cl^-}$) are oxidized to produce chlorine gas ($\mathrm{2Cl^-(aq) \rightarrow Cl_2(g) + 2e^-}$). At the cathode, water is reduced to produce hydrogen gas and hydroxide ions ($\mathrm{2H_2O(l) + 2e^- \rightarrow H_2(g) + 2OH^-(aq)}$). The sodium ions ($\mathrm{Na^+}$) remaining in the solution combine with the hydroxide ions ($\mathrm{OH^-}$) to form sodium hydroxide ($\mathrm{NaOH}$). The overall reaction is: $\mathrm{2NaCl(aq) + 2H_2O(l) \rightarrow 2NaOH(aq) + Cl_2(g) + H_2(g)}$. The name "Chloralkali" is derived from the products: "chlor" for chlorine and "alkali" for sodium hydroxide (an alkali).

The incorrect option is (1): Contact Process. The Contact Process is used for the industrial manufacture of sulfuric acid ($\mathrm{H_2SO_4}$) from sulfur dioxide ($\mathrm{SO_2}$), not for the electrolysis of $\mathrm{NaCl}$.

The incorrect option is (2): Dargen Process. The "Dargen Process" is not a recognized name for a standard chemical industrial process.

The incorrect option is (4): Haber's Process. Haber's Process is an industrial method for producing ammonia ($\mathrm{NH_3}$) from nitrogen ($\mathrm{N_2}$) and hydrogen ($\mathrm{H_2}$), typically using an iron catalyst under high pressure and temperature.