(a) Explain the term electrolyte and give two examples. (b) State the relationship between the mass of a substance liberated during electrolysis and the cha...

Answer Details

(a) Electrolyte

An electrolyte is a substance (usually a molten ionic compound or an aqueous solution of an acid, base or salt) that conducts electric current by the movement of its free ions and is chemically decomposed in the process.

Two examples:

• Dilute tetraoxosulphate(VI) acid (dilute H₂SO₄).
• Copper(II) tetraoxosulphate(VI) solution (CuSO₄ solution); acidified water or sodium chloride solution are also acceptable.

(b) Mass liberated and charge passed

By Faraday's first law of electrolysis, the mass m of a substance liberated at an electrode is directly proportional to the quantity of electric charge Q that passes through the electrolyte: \[ m \propto Q \Rightarrow m = z Q = z I t \]

where z is the electrochemical equivalent of the substance, I the current and t the time.