What is the difference between alkanes, alkenes and alkynes?

In brief, Alkanes are saturated hydrocarbons meaning a single bond between the carbon-carbon atoms eg Ethane. Alkenes are unsaturated hydrocarbons meaning one or more double bonds between carbon-carbon atoms eg Ethene. Alkynes are also unsaturated hydrocarbons with one or more triple bonds between the carbon-carbon atoms eg Ethyne.