Identify which functional group is $NOT$ present in the given compound.

Which of the following $C_6H_6$ compounds has a single set of structurally equivalent hydrogen atoms? The structures are labeled $I$ to $V$ as shown in the image.

An organic compound $C_3H_6O$ does not give a precipitate with $2,4-$Dinitrophenylhydrazine reagent and does not react with metallic sodium. The compound is:

How many functional groups are present in the following molecule?

How many secondary carbon and hydrogen atoms are present in the molecule $CH_3-CH(Br)-CH(Br)-CH_3$ respectively?

State whether the following statements are True or False:
$(i)$ There is a huge number of organic compounds because the carbon atom is very small.
$(ii)$ The number of organic compounds is huge because of catenation.
$(iii)$ Organic compounds are in a huge number because of valency.