Alkanes

Topic Content:

Alkane forms a homologous series of saturated hydrocarbons. They have the general molecular formula of C_n H_2n+2 (where n = 1, 2, 3…). All the carbon atoms in alkanes are tetrahedrally bonded. The carbon atoms are sp³ hybridized. They are chemically more stable compared to alkenes and alkynes.

Methane (CH ₄ ):

Hybridization = sp³        

Bond angle = 109.5°

Laboratory Preparation of Methane:

Methane gas is prepared in the laboratory by heating sodium ethanoate (sodium acetate) with soda-lime as shown in the diagram for the laboratory set-up above.

\( \scriptsize CH_3COONa \: + \: NaOH \: \rightarrow \: \underset{methane}{CH_4} \: + \: Na_2CO_3 \)

A mixture of sodium ethanoate (sodium acetate) and soda-lime is taken in a hard glass test tube in the ratio of 1:3. The mixture is heated; as