1. During the electrolysis of molten lead bromide, a graphite anode is preferred because graphite remains unaffected by the reactive bromine vapours which are released at the anode.

2. Sulphuric acid is a strong acid compared to acetic acid. A strong acid has more ions than a weak one, and so, its solution will be a better electrical conductor than a weak acid. So, electrical conductivity of acetic acid is less in comparison of electric conductivity of sulphuric acid.

3. In the electrolysis of molten lead bromide, the following reactions take place:

At the cathode :  Pb²⁺ (l) + 2e^– → Pb(l)

At the anode : 2Br (l) → Br₂ (g) + 2e^–

Lead (II) ions (Pb²⁺ ) are attracted to the negative electrode, and the Pb²⁺ ions are forced to accept two electrons. Pb²⁺ ions are reduced. Bromide ions (Br^– ) are attracted to the positive electrode and the bromide ions are forced to give away their extra electron to form bromine atoms. Thus, bromide ions are oxidised. So, electrolysis of molten lead bromide is a redox reaction