Electrolysis of aqueous solutions

What additional ions are present in aqueous solutions during electrolysis?

H⁺ and OH⁻ ions from water.

Which ion is discharged at the cathode if two positive ions are present?

The least reactive ion.

What is produced at the cathode during the electrolysis of aqueous sodium chloride?

Hydrogen gas (H₂)

What is produced at the anode during the electrolysis of aqueous sodium chloride?

Chlorine gas (Cl₂)

Write the half-equation for the reduction of hydrogen ions during electrolysis.

2H++2e−→H2​

Write the half-equation for the oxidation of hydroxide ions during electrolysis.

4OH−→2H2​O+O2​+4e−

What is the test for chlorine gas?

Turns damp blue litmus paper red and then bleaches it.

What is the test for oxygen gas?

Relights a glowing splint.

What factors affect the products of electrolysis in aqueous solutions?

The reactivity of the metal, the concentration of the ions, and the type of electrolyte.

Why is hydrogen produced instead of sodium during the electrolysis of aqueous sodium chloride?

Sodium is more reactive than hydrogen.

Why is copper deposited at the cathode during the electrolysis of copper(II) sulfate solution?

Copper is less reactive than hydrogen.

What happens to the mass of the cathode during the electrolysis of copper(II) sulfate solution?

It increases as copper is deposited.

Write the overall equation for the electrolysis of water.

2H2​O→2H2​+O2​

What is the use of electrolysis in industry?

Extraction of metals, purification of metals, and production of gases like hydrogen and chlorine.

Why are inert electrodes used in some electrolysis processes?

To prevent the electrodes from reacting with the electrolyte or products.