If a concentrated solution of potassium bromide is electrolysed, what gas will be produced at the cathode?

Molten lead bromide

Explanation:

PbBr 2 (l), is an electrolyte. During electrolysis: Pb 2 + ions gain electrons at the cathode and become Pb atoms. Br - ions lose electrons at the anode and become Br atoms, which pair up to form Br 2 molecules.