Alcohol forms a homologous series with general formula $C_nH_{2n + 1} - OH$ and -OH group as functional group. Ethanol is commonly called alcohol and is used in alcoholic drinks. It is good solvent, used in medicines, cough syrups, tonics etc.

(a) Write structural formula and name of 4th member of alcohol homologous series.

(b) What happens when ethanol is heated with alkaline $KMnO_4$? Write chemical equation involved.

(c) Write the chemical equation of reaction of ethanol with ethanoic acid in the presence of concentrated $H_2SO_4$. Write the name of this reaction.

OR

(c) What happens when ethanol is heated with excess concentrated sulphuric acid at $443 K$? Write chemical equation involved. What is the role of concentrated sulphuric acid in this reaction?

(a) The structural formula of the 4th member of the alcohol homologous series is $CH_3CH_2CH_2CH_2OH$, and its name is Butan-1-ol.

(b) When ethanol is heated with alkaline $KMnO_4$, it gets oxidized to ethanoic acid. The chemical equation involved is:

$$CH_3CH_2OH + 2KMnO_4 \rightarrow CH_3COOH + 2MnO_2 + 2KOH + H_2O$$

(c) When ethanol reacts with ethanoic acid in the presence of concentrated $H_2SO_4$, it forms ethyl ethanoate. The chemical equation involved is:

$$CH_3CH_2OH + CH_3COOH \rightarrow CH_3COOCH_2CH_3 + H_2O$$

This reaction is known as esterification.

OR

(c) When ethanol is heated with excess concentrated sulphuric acid at $443 K$, it forms ethene. The chemical equation involved is:

$$CH_3CH_2OH \rightarrow CH_2=CH_2 + H_2O$$

Concentrated sulphuric acid acts as a dehydrating agent in this reaction.