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).