Question

NAOH is obtained by the electrolysis of​

Answer 1

Explanation:

Sodium hydroxide, NaOH, is also known as lye or caustic soda.

Sodium hydroxide is a commonly used base.

Electrolysis of concentrated sodium chloride solutions (brine) produces chlorine gas, hydrogen gas and aqueous sodium hydroxide.

2NaCl(aq) + 2H2O(l) → H2(g) + Cl2(g) + 2NaOH(aq)

Cl2(g) is produced at the anode (positive electrode).

H2(g) and NaOH(aq) are produced at the cathode (negative electrode).

Three types of electrolytic cell are used to produce sodium hydroxide from brine:

Castner-Kellner Cell (Mercury Process)

Nelson Diaphragm Cell

Membrane Cell

Answer 2

Answer:

• NaOH is prepared by the electrolysis of NaCl solution with graphite at anode and iron at cathode.

      Reaction at anode [ Oxidation ]

2Cl⁻₍aq₎ ---------> Cl₂+2e⁻

      Reaction at cathode [ Reduction ]

2H₂O₍l₎+2e⁻ -----------> H₂₍g₎+2OH⁻₍aq₎

Overall reaction or net reaction :

2H₂O+2Cl⁻₍aq₎+2Na⁺₍aq₎ -------------> 2Na₍aq₎+2OH⁻₍aq₎+H₂+Cl₂

• During electrolysis of aqueous sodium hydroxide solution, hydrogen is liberated at cathode in preference to sodium.
• This is because H⁺ ions have higher reduction potential than Na⁺ ions
• When fused sodium hydroxide is used for the electrolysis, sodium is discharged at cathode.

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