IGCSE Chemistry Electrochemistry topical questions

Molten sodium chloride is electrolysed using inert electrodes.

1. (a)Name the electrolyte in this cell.[1]
2. (b)State the product formed at the cathode.[1]
3. (c)State the product formed at the anode.[1]

A student sets up a cell with two graphite rods dipped into a solution of copper(II) sulfate.

1. (a)Identify the electrolyte.[1]
2. (b)State one observation at the cathode.[1]

Molten potassium iodide is electrolysed using inert electrodes.

1. (a)Name the ion that moves to the cathode.[1]
2. (b)Name the product formed at the cathode.[1]
3. (c)Name the product formed at the anode.[1]

Dilute sulfuric acid is electrolysed using platinum electrodes.

1. (a)Name the product formed at the cathode.[1]
2. (b)Name the product formed at the anode.[1]
3. (c)Write the ionic half-equation for the reaction at the cathode.[2]

Solid lead(II) bromide does not conduct electricity, but when it is melted it conducts and the molten liquid is decomposed by the current. Explain these observations.

Aqueous magnesium sulfate is electrolysed using inert electrodes.

1. (a)Name the product formed at the cathode.[1]
2. (b)Explain why magnesium is not deposited at the cathode.[1]
3. (c)Name the product formed at the anode.[1]
4. (d)Write the ionic half-equation for the reaction at the anode. (Supplement)[1]

Concentrated sodium chloride solution (brine) is electrolysed using inert electrodes.

1. (a)Name the gas formed at the cathode.[1]
2. (b)Name the gas formed at the anode.[1]
3. (c)Explain why chlorine, rather than oxygen, is produced at the anode.[1]
4. (d)State one safety precaution for handling the gas in part (b).[1]

A metal key is to be electroplated with nickel.

1. (a)State the material of the anode.[1]
2. (b)State what the key is connected to.[1]
3. (c)Explain why the anode gradually gets smaller during the process.[2]

Hydrogen–oxygen fuel cells are used to power some buses and cars.

1. (a)State the two substances that react in the cell.[1]
2. (b)Explain one environmental advantage of this cell over a petrol engine.[2]
3. (c)State one disadvantage of hydrogen–oxygen fuel cells.[1]

Molten lithium chloride is electrolysed using inert electrodes.

1. (a)Write the ionic half-equation for the reaction at the cathode.[1]
2. (b)Write the ionic half-equation for the reaction at the anode.[1]
3. (c)Describe how charge is carried through the electrolyte. (Supplement)[1]
4. (d)Explain how the two electrode reactions together keep a current flowing around the circuit. (Supplement)[2]