A concentrated aqueous solution containing between 3.5% and 26% sodium chloride.

A positively charged electrode, in an electrolysis cell, to which the anions are attracted.

A negatively charged electrode, in an electrolysis cell, to which the cations are attracted.

Reduction is a type of reaction in which a substance loses oxygen or gains electrons.

Oxidation is a type of reaction in which a substance gains oxygen or loses electrons.

Electrolysis: brine

Combined science

Principles of electrolysis

Electrolysis of molten salts

Electrolysis: extracting aluminium

Electrolysis of aqueous solutions

Electrolysis: purifying copper

Electrolysis: aqueous solutions practical

Half equations: electrolysis

In the Using Earth's Resources unit, pupils learned about the extraction, production and uses of hydrocarbons from crude oil, as well as metal extraction.

This unit focuses on electrolysis, electrode reactions, and predicting products, including competing reactions in solutions. It explains metal extraction through electrolysis and writing ionic equations. It also covers tests for gases like oxygen, hydrogen, carbon dioxide, and chlorine.

Electrolysis

What ions are present in a solution of brine?

What is produced at the negative electrode during the electrolysis of brine?

What is the half-equation for the reaction at the anode during electrolysis of brine?

because chlorine ions are discharged at the anode

because hydrogen ions are discharged at the cathode

because sodium hydroxide forms in the solution

Why does the electrolyte become alkaline during the electrolysis of brine?

Hydrogen ions are oxidised at the cathode.

Hydroxide ions remain in the electrolysis cell at the end of the reaction.

Which of the following statements describes what happens during the electrolysis of brine? 

Which subatomic particle has a negative charge?

a gas that reacts with electrodes, producing ions

a liquid or solution that contains freely moving ions

a solid that conducts electricity, providing a circuit

Which ion is discharged at the cathode during the electrolysis of aqueous solutions?

Which of the following definitions of oxidation are correct?

the position of the metal in the reactivity series 

What determines whether hydrogen or a metal is produced at the anode during electrolysis?

What is produced at the anode during the electrolysis of an aqueous solution?

Electrolysis: brine

Lesson outcome