Acetone and acetaldehyde are

Give the name and structure of the following:
$(i)$ Chain isomers of pentane $(C_5H_{12})$
$(ii)$ Isomers of $C_3H_8O$
$(iii)$ Isomers of $C_3H_6O$
$(iv)$ Metamers in $C_4H_{10}O$

Which of the following pairs represents types of stereoisomerism?

The total number of stereoisomers possible for the given compound $1,3,5$-tribromocyclohexane is:

Which one of the following is most reactive towards electrophilic reagent?

Which of the following shows keto-enol isomerism?