How many structural isomers are possible for a compound with molecular formula $C_3H_7Cl$?

Which of the following is not an isomer of $but-1-yne$?

Explain the following terms:
$(a)$ Isomerism
$(b)$ Position isomerism
$(c)$ Chain isomerism
$(d)$ Functional group isomerism
$(e)$ Metamerism
$(f)$ Optical isomerism

What is the number of structural isomers of $C_3H_6O$?

Which of the following pairs are isomers?

Which one of the following isomeric structures has the lowest energy?