Question

How is ethane prepared in the laboratory?

Answer 1

Hint : Ethane can be prepared in any laboratory with the help of sodium propionate and soda lime. The by-product sodium carbonate will be obtained at the end of the reaction. Use of quick lime as a catalyst can help the reaction.

Complete Step By Step Answer:
The laboratory preparation of ethane is given as follows,
When the mixture of sodium propionate and soda lime is taken into a boiling tube and is heated, ethane gas is evolved from it.
The chemical formula of sodium propionate is ${{C}_{2}}{{H}_{5}}COONa$ and the chemical formula of soda lime is $NaOH$ .
The reaction for the preparation of ethane in the laboratory is given below.
${{C}_{2}}{{H}_{5}}COONa+NaOH\xrightarrow{CaO,{{300}^{\circ }}C}N{{a}_{2}}C{{O}_{3}}+{{C}_{2}}{{H}_{6}}$
Here sodium carbonate ( $N{{a}_{2}}C{{O}_{3}}$ ) is obtained as the by-product from the reaction occurred. The ethane obtained is collected by downward displacement of the water method.
As shown in the above given reaction, the $COONa$ group has been replaced in ${{C}_{2}}{{H}_{5}}COONa$ with one hydrogen ( $H$ ), which forms ${{C}_{2}}{{H}_{6}}$ and $NaOH$ gets attached to $COONa$ and makes $N{{a}_{2}}C{{O}_{3}}$ as a by-product.
This reaction occurs with the help of quicklime ( $CaO$ ), and this reaction occurs at ${{300}^{\circ }}$ Celsius.
Quicklime ( $CaO$ ) is also known as burnt lime.
Although, this is not the only method with which ethane can be prepared in any laboratory.
Ethane can be prepared in the laboratory by cracking hydrocarbons. It can be prepared by cracking hydrocarbons such as kerosene or wax.
It can also be prepared from ethanol, for this we have to heat ethanol with excess concentrated sulphuric acid at $160-{{170}^{\circ }}$ Celsius.

Note :
The preparation of ethane gas in the laboratory can be done by more than one method as shown. Also in the first method, calcium oxide is important as a catalyst, without the catalyst, the reaction will occur really slowly.