Which of the following is the use of acetic acid?

Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements. Give reasons.

$A$ carboxylic acid (molecular formula $C_{2}H_{4}O_{2}$) reacts with an alcohol in the presence of an acid catalyst to form a compound $'X'$. The alcohol on oxidation with alkaline $KMnO_{4}$ followed by acidification gives the same carboxylic acid $C_{2}H_{4}O_{2}$. Write the name and structure of $(i)$ carboxylic acid,$(ii)$ alcohol,and $(iii)$ the compound $'X'$.

Complete the following chemical reactions and write the chemical name of the products obtained.
$(i)$ $CH_{2}=CH_{2} + H_{2}O \longrightarrow$
$(ii)$ $CH_{3}COOH + NaOH \longrightarrow$
$(iii)$ $CH_{3}CH_{2}OH \xrightarrow{H_{2}SO_{4}} $
$(iv)$ $HCOOH + Na \longrightarrow$
$(v)$ $C_{2}H_{5}OH \xrightarrow{\text{Alk. } KMnO_{4}} $

Give names of the following:
$(a)$ An alcohol containing $4$ carbon atoms.
$(b)$ An acid with $5$ carbon atoms.
$(c)$ Simplest ketone. Define functional group in a carbon compound. Mention names of any three functional groups with their formulae and example.

Which of the following compounds is obtained by the fermentation reaction of molasses?