Which products are formed in the chlor-alkali process when electricity is passed through an aqueous sodium chloride solution?
NaCl(aq) + H2O(I) → Products
- AOption (a)
NaCl + H2
- BOption (b)
NaHCO3 + Cl2
- COption (c)
H2 + O2
- DOption (d)
NaOH + H2 + Cl2
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Correct answer
NaOH + H2 + Cl2
Why this answer is correct
The correct answer is NaOH + H2 + Cl2.
Key Points
- The chlor-alkali process involves the electrolysis of an aqueous sodium chloride (NaCl) solution, also known as brine.
- When electricity is passed through the brine, it decomposes into three main products: sodium hydroxide (NaOH), chlorine gas (Cl2), and hydrogen gas (H2).
- The reactions occurring at the electrodes are:
- Cathode (Reduction): 2H2O + 2e- → H2 + 2OH-
- Anode (Oxidation): 2Cl- → Cl2 + 2e-
- The sodium ions (Na+) in the solution combine with the hydroxide ions (OH-) to form sodium hydroxide (NaOH).
- The products NaOH, H2, and Cl2 are commercially valuable. Sodium hydroxide is used in the manufacture of paper, soap, and detergents. Chlorine is used for disinfecting water, in the production of PVC, and in the manufacture of various chemicals. Hydrogen is used in hydrogenation processes and as a fuel.
Additional Information
- NaCl + H2
- This option is incorrect because sodium chloride (NaCl) is the reactant, not the product, in the chlor-alkali process.
- Hydrogen gas (H2) is indeed produced, but not sodium chloride.
- NaHCO3 + Cl2
- This option is incorrect because sodium bicarbonate (NaHCO3) is not produced in the chlor-alkali process.
- Chlorine gas (Cl2) is produced, but not sodium bicarbonate.
- H2 + O2
- This option is incorrect because oxygen gas (O2) is not produced in the chlor-alkali process.
- Hydrogen gas (H2) is produced, but not oxygen.