F.5 Electrolysis

Why does solid lead bromide not conduct electricity, while molten lead bromide does?

• Solid lead bromide has a higher melting point.

• Ions in solid lead bromide are fixed in a lattice and cannot move, but are free to move in the molten state.

• Molten lead bromide is a better insulator than solid lead bromide.

• Solid lead bromide reacts with the electrodes, preventing current flow.

During the electrolysis of molten lead bromide, what substances are produced at the negative and positive electrodes, respectively?

• Lead at the positive electrode, Bromine at the negative electrode

• Bromine at the positive electrode, Lead at the negative electrode

• Lead at both electrodes

• Bromine at both electrodes

When molten zinc chloride undergoes electrolysis, what gas is produced at the positive electrode, and how is it identified?

• Oxygen, which relights a glowing splint.

• Hydrogen, which makes a 'pop' sound with a lit splint.

• Chlorine, which turns damp blue litmus paper red and bleaches it lighter.

• Zinc, which forms a silvery metallic bead.

Which of the following half-equations take place in the negative electrode?