Question

Which pair below represents isomers ?

• A. $C{H}_{3}C{H}_{2}C{H}_{2}OH$ and $HOC{H}_{2}C{H}_{2}C{H}_{2}C{H}_3$
• B. $C{H}_{3}C{H}_{2}C{H}_3$ and $C{H}_{3}C{H}_{2}C{H}_{2}C{H}_3$
• C. $C{H}_{3}CH\left(Cl\right)C{H}_3$ and $C{H}_{3}C{H}_{2}C{H}_{2}Cl$
• D. $C{H}_{3}COC{H}_3$and $C{H}_{3}C{H}_{2}C{H}_{2}CHO$

Answer 1

The correct option is C $C{H}_{3}CH\left(Cl\right)C{H}_3$ and $C{H}_{3}C{H}_{2}C{H}_{2}Cl$

Isomers are the compounds having same molecular formula but different properties due to difference in arrangement of atoms. $C{H}_{3}CHClC{H}_3$ and $C{H}_{3}C{H}_{2}Cl$ both have same molecular formula $C_3{H}_{7}Cl$ Thus they are positional isomers.
In all other options, the molecular formula of the two cmpounds are not same. So, the correct answer is option (c).