Given the following set of structural formulas, how many different constitutional isomers are represented?

Which of the following statements correctly describes the number of possible constitutional isomers for $C_4{H}_9{\mathrm{Br}}_{}$ (butyl bromide)?

Given the two compounds $C_4{H}_{10}$ (n-butane) and $C_4{H}_{10}$ (isobutane), identify the relationship between these two compounds.

All of the following are representations of 2-methylpentane except:

Classify the following pair of compounds: $C_4{H}_{10}$ (butane) and $C_4{H}_{10}$ (2-methylpropane). Select the single best answer.

Which of the following pairs are constitutional isomers of $C_2{H}_6{O}_2$?

Which of the following statements is correct regarding the constitutional isomers of $C_5{H}_{12}$?

How many distinct constitutional isomers are possible for the molecular formula $C_2{\mathrm{Cl}}_3{F}_3$?

Which of the following pairs are constitutional isomers of $C_2{H}_3{\mathrm{Cl}}_3$?