What type of isomerism is observed between $n$-butyl alcohol and isobutyl alcohol?

Which of the following is not found in alkenes?

Write the types of isomers for $C_4H_6$ (alkyne) and provide one example for each.

Choose the pair of chain isomers.

Which molecular formula does not exhibit chain isomerism?

Assertion $A$: Enol form of acetone $[CH_{3}COCH_{3}]$ exists in $< 0.1 \%$ quantity. However,the enol form of acetylacetone $[CH_{3}COCH_{2}COCH_{3}]$ exists in approximately $15 \%$ quantity.
Reason $R$: Enol form of acetylacetone is stabilized by intramolecular hydrogen bonding,which is not possible in the enol form of acetone. Choose the correct statement: