Alkanes

Alkane definition

Saturated hydrocarbons containing only single C–C bonds

General formula

CₙH₂ₙ₊₂

Bond type

Single covalent bonds only

Saturated meaning

No double or triple bonds; cannot undergo addition reactions

Homologous series

Alkanes form a homologous series with similar properties

Trend in boiling point

Increases as chain length increases

Trend in flammability

Decreases as chain length increases

Trend in viscosity

Increases as chain length increases

Solubility

Insoluble in water (non‑polar)

Reactivity

Generally unreactive due to strong C–C and C–H bonds

Main reactions

Combustion and substitution

Complete combustion

Alkane + oxygen → CO₂ + H₂O

Incomplete combustion

Alkane + oxygen → CO + C + H₂O

Substitution reaction

Alkane + halogen → haloalkane + hydrogen halide

Substitution condition

Requires UV light

Example substitution

Methane + chlorine → chloromethane + HCl

Uses of alkanes

Fuels (methane, propane, butane, petrol)

Methane formula

CH₄

Ethane formula

C₂H₆

Propane formula

C₃H₈

Butane formula

C₄H₁₀

Key idea

Alkanes are saturated, fairly unreactive hydrocarbons used mainly as fuels

methane displayed formula

ethane displayed formula

propane displayed formula

butane displayed formula

pentane displayed formula