Chapter 10

What is the defining characteristic of free radicals?

• All electrons are paired

• Contain an unpaired electron

• High stability

• Form stable organic species

What type of orbital does the unpaired electron reside in an alkyl radical?

• 2p

• 3p

• 1s

• 2s

What is the stability trend of alkyl radicals?

• Stability is not related to substitution

• More substituted alkyl radicals are more stable

• Alkyl radicals have no stability trend

• Less substituted alkyl radicals are more stable

What is the purpose of homolytic bond dissociation energies?

• To measure the stability of alkenes

• To measure the stability of carbocations

• To measure the stability of alkyl radicals

• To measure the stability of alkynes

Which halogen is most reactive in alkane halogenation?

• I2

• F2

• Br2

• Cl2

What is the first step in the initiation of alkane halogenation?

• Formation of HX and an alkyl radical

• Formation of R–X and regeneration of the X· radical

• Splitting of a halogen molecule into two X· radicals

• Combining of radicals to form undesired even-electron products

Why is chlorination not very selective in halogenation?

• It is highly selective for tertiary C–H

• It gives mixtures of products with substitution at different C–H groups

• It is insensitive to solvent polarity

• It gives monobromination products selectively

What is the selectivity of bromination in halogenation?

• Highly selective for primary C–H

• Highly selective for quaternary C–H

• Highly selective for secondary C–H

• Highly selective for tertiary C–H

What is a free radical?

• A molecule with all electrons paired

• A molecule with an unpaired electron

• A stable organic species

• An intermediate in organic reactions

What type of orbital does the unpaired electron reside in an alkyl radical?

• 1s

• 3p

• 2s

• 2p