Question

In full detail, explain what happens during the electrolysis of a NaCl brine? Be sure to identify what is being oxidized and what is being reduced (2). Identify where in the cell the reactions are taking place (2).

Answer 1

Answer:

Explanation:

Electrolysis of aqeous sodium chloride(NaCl)

Electrolysis is a process that converts electrical energy into chemical energy.

Electrolytic processes involves three major steps:

1. Ionization of electrolyte and water

2. Migration of ions to electrodes

3. Discharge of ions at the electrodes.

For the Electrolysis of brine, we follow these three steps:

1. Ionization of the aqeous brine solution:

NaCl → Na⁺ + Cl⁻

H₂O ⇄H⁺ + OH⁻

2. Migration of ions to the electrodes

The positive charges Na⁺ and H⁺ would both go to the cathode which is the negatively charged electrode

The negative charges Cl⁻ and OH⁻ migrates to the anode which are the positively charged electrodes. The anode is positively charged electrode.

3. Discharge of ions at the electrodes.

The preferential discharge of ions is based on the activity series and concentration of the ions.

On the activity series H is lower and it discharges preferentially to Na in the cathode:

2H⁺ + 2e⁻ → H₂

At this electrode, the cathode, reduction occurs and H⁺ ions are reduced.

At the anode Cl⁻ and OH⁻ migrates. But Cl⁻ is discharged preferentially due to its higher concentration.

2Cl⁻ ⇄ Cl₂ + 2e⁻

This is the oxidation half and Cl is oxidized