Electrolysis

IGCSE Edexcel Chemistry

Electrolysis

A chemical change caused by passing an electric current through a compound that is molten or in a solution.

Electrolyte

A liquid or solution that undergoes the process of electrolysis.

Ionic Compounds

Compounds that conduct electricity when molten or in aqueous state, as ions are free to move.

Covalent Compounds

Compounds that do not conduct electricity because they consist of individual molecules without an overall electrical charge.

Anode

The electrode where oxidation occurs; positive electrode attracting negative ions.

Cathode

The electrode where reduction occurs; negative electrode attracting positive ions.

Oxidation

The loss of electrons or the gain of oxygen.

Reduction

The gain of electrons or the loss of oxygen.

Reactivity Series

A list of metals ranked by their reactivity, determining which will displace hydrogen in electrolysis.

Cations

Positively charged ions.

Anions

Negatively charged ions.

Half-Ionic Equations

Equations that show the reduction and oxidation processes at the anode and cathode during electrolysis.

NaOH

Sodium Hydroxide, formed in the electrolysis of aqueous sodium chloride.

OILRIG

An acronym meaning 'Oxidation Is Loss, Reduction Is Gain' that summarizes oxidation and reduction.

PANIC

An acronym meaning 'Positive Anode, Negative Is Cathode' that helps remember electrode charges.

Chlorine Gas Formation

Chlorine gas produced at the anode during the electrolysis of concentrated sodium chloride solution.

Water Splitting

The process where water splits into hydrogen and hydroxide ions, participating in electrolysis.

Conductivity in Ionic Compounds

Ionic compounds conduct electricity in molten or aqueous states due to free-moving ions.

Electrodes

Electric conductors used to carry current into the non-metallic substances during electrolysis.

Hydrogen Production

In electrolysis, the rate of hydrogen production is twice that of oxygen when using dilute sulfuric acid.

Dilute Sulfuric Acid Electrolysis

Electrolysis process that produces more hydrogen gas than oxygen due to the greater number of hydrogen ions.