Electrolysis

Electrolysis

1.

1. An ionic compound in the liquid or aqueous state.
2. In the cathode the oxygen is produced and it has less reaction than sodium. At the anode chlorine discharges and it discharges more easier than hydrogen. Sodium loses an electron at the anode and Sodium gains an electron at the cathode. This means that is discharged more easily. 

1

Molten sodium chloride is decomposed into sodium and chlorine by electrolysis, sodium chloride is an ionic compound. Both molten and aqueous sodium chloride will conduct electricity because the ions are free to move.

2

1. K+,  Mg2+
2. F-, Cl-, So42-

3

1	Electrolyte	3	A process in which electrical energy from a direct current decomposes.
2	Electrolysis	2	To break down a compound into simpler compounds or into elements.
3	Decomposition	1	An ionic compound which conducts electricity when molten or dissolved in water.

1

	Product at the cathode	product at the anode
Sodium chloride	Lead	Bromine
Potassium iodide	Potassium	Iodine
Copper chloride	Copper	Chlorine

2

1. Potassium
2. Bromine

3

1. Molten
2. Molten
3. When it is molten the ions are free to move and that helps them to be able to conduct electricity. In the solid state they are fixed in position by the 3D ionic lattice.

1

2

1. Reduction
2. Oxidation

3

1. At the anode 
2. At the cathode
3. At the anode electrons are lost which is defined as reduction and in the cathode electrons are gained which is defined as oxidation.

1

1. K+, Cl-
2.  I. Anode chloride   II. Cathode potassium
3. Potassium and chlorine

2 

Na+, I-, H+ and OH-

3

1. Copper
2. Oxygen

4

1. Cl- (aq), H+ (aq), K+ (aq), OH- (aq)
2. Cl2 (g), H2 (g)

1

1. 1 mark
2. How hydroxide ions lose its electrons and how copper gains electrons. Explain that ions are attracted to opposite charged electrodes.

2

When hydroxide makes contact with the ion gains one electron, while the copper gains two electrons when its in contact with the cathode and it discharges. Positive ions are attracted to the cathode and negative to the anode as opposites are attracted to one another.

1

1. Electrolyte is an ionic compound in a aqueous or molten state.
2. I. Solution: are the ions free to move? The solute is dissolved in water. Some water is ionised.

   Hydrogen: Why is sodium not a product? What happens to the ions?

II. Chlorine is discharged easier than OH-, so it causes a discharge at the anode and that produces chlorine. In NaCl there are OH- and H+  because it’s aqueous and the hydrogen is less reactive than sodium and that make it easier to be discharged.

1

1. H and F because they conduct electricity.
2. The K2S04 is aqueous so there are H+ and OH- ions present. As the hydrogen is less reactive than the potassium then it is discharged more easily. Hydroxide is discharged more easily than sulfate so it is discharged at the anode which produces oxygen.