Chapter 21, Problem 6RQ

Distinguish between isomerism and resonance. Distinguish between structural and geometric isomerism. When writing the various structural isomers, the most difficult task is identifying which are different isomers and which are identical to a previously written structure_—that is, which are compounds that differ only by the rotation of a carbon single bond. How do you distinguish between structural isomers and those that are identical?

Alkenes and cycloalkanes are structural isomers of each other. Give an example of each using C₄H₈. Another common feature of alkenes and cycloalkanes is that both have restricted rotation about one or more bonds in the compound, so both can exhibit cis- trans isomerism. What is required for an alkene or cycloalkane to exhibit cis-trans isomerism? Explain the difference between cis and trans isomers.

Alcohols and ethers are structural isomers of each other, as are aldehydes and ketones. Give an example of each to illustrate. Which functional group in Table 21-4 can be structural isomers of carboxylic acids?

What is optical isomerism? What do you look for to determine whether an organic compound exhibits optical isomerism? 1-Bromo-1-chloroethane is optically active whereas 1-bromo-2-chloroethane is not optically active. Explain.