How Many Structural Isomers are Possible for a Substance Having

Question

How many structural isomers are possible for a substance having the molecular formula C₄H₁₀?
A)1
B)2
C)4
D)3
E)11

Accepted Answer

The molecular formula C₄H₁₀ can form 2 structural isomers: n-butane and isobutane (or methylpropane).