Name the functional group present in the following compounds:
$(i)$ $CH_{3}-CH_{2}-CH_{2}-COOH$
$(ii)$ $CH_{3}-CO-CH_{2}-CH_{3}$

Identify the unsaturated compounds from the following:
$(i)$ Propane
$(ii)$ Propene
$(iii)$ Propyne
$(iv)$ Chloropropane

$(a)$ How is vinegar made?
$(b)$ What is glacial acetic acid? What is its melting point?
$(c)$ Why are carboxylic acids called weak acids?
$(d)$ Write the name and the formula of the two compounds formed when the ester $CH_{3}COOC_{2}H_{5}$ undergoes saponification.

What is the percentage of sulfur used in vulcanized rubber for battery casings (in $\%$)?

An organic compound $A$ on heating with concentrated $H_2SO_4$ forms a compound $B$, which on addition of one mole of hydrogen in the presence of $Ni$ forms a compound $C$. One mole of compound $C$ on combustion forms two moles of $CO_2$ and $3$ moles of $H_2O$. Identify the compounds $A$, $B$, and $C$ and write the chemical equations of the reactions involved.

Which substance is produced by the reduction of methanal in the presence of a palladium catalyst?