Question

How will you convert ethanal into the following compounds? Give the chemical equation involved.
(i)

(ii)

(iii) $C{H_3}C{H_2}OH$

Answer 1

Hint: In the conversion of ethanal to the given compounds different named reactions can be applied. The named reaction used for the conversion is Clemmensen reduction. The ethanal can be converted to alcohol using a reducing agent.

Complete step by step answer:
The reaction for the conversion of ethanal to alkane is shown below.

The conversion of ethanal to alkane is done by Clemmensen reduction. In Clemmensen reduction aldehydes or ketones are reduced to alkanes by reacting with hydrochloric acid and zinc amalgam.
In this reaction, ethanal is treated with hydrochloric acid in presence of zinc amalgam to form ethane.
(ii) Conversion of ethanal to 3-Hydroxybutanal.

The conversion of ethanal to 3-hydroxybutanal is done by Aldol condensation. In aldol condensation aldehyde carrying a $\alpha$-hydrogen is treated with a base to form a $\beta$-hydroxy aldehyde which is known as aldol. In the aldol condensation reaction two molecules of aldehyde are reacted.
In this reaction two molecules of ethanal react with dilute sodium hydroxide to give 3-Hydroxybutanal. In the product at $\beta$-position a hydroxyl group is attached.
(iii) Conversion of ethanal to ethanol.

Ethanal is converted to ethanol with the help of lithium aluminium hydride$(LiAl{H_4})$. Lithium aluminium hydride is a reducing agent.
In this reaction ethanal is reacted with lithium aluminium hydride where ether is used as a solvent to give ethanol.

Note: There are other reducing agents which can be used to convert aldehyde to alcohol. The reducing agents are sodium borohydride $(NaB{H_4})$, ${H_2}$ and $Ni/Pt/Pd$. In aldol condensation if $\alpha$-hydrogen is not present, reaction does not take place. It's mandatory to have a $\alpha$-hydrogen, else the reaction is said as a Cannizaro reaction.