When an electric current is passed through the circuit shown for a set time, 0.54 g of silver is deposited on the cathode in cell I (silver nitrate). Cell II contains copper(II) sulphate and cell III dilute sulphuric acid. In cell III hydrogen is produced: 2H⁺ + 2e⁻ → H₂. (Ar Ag = 108, Cu = 64; 1 mole of gas = 24 dm³ at r.t.p.)

1. aWhich electrode is the cathode in cell I? [1]
2. bAt which electrode is copper deposited in cell II? [1]
3. cWrite an equation for the formation of silver at the cathode in cell I. [1]
4. dHow many moles of electrons were used to produce 0.54 g of silver? [2]
5. eCalculate the mass of copper deposited at the cathode in cell II. [3]
6. fCalculate the volume of hydrogen produced in cell III at r.t.p. [2]

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