91Ó°ÊÓ

Despite the limitations of radical chlorination of alkanes, the reaction is still useful for synthesizing certain halogenated compounds. For which of the following compounds does radical chlorination give a single monochloro product?

What is the difference between a transition state and an intermediate?

Draw an energy diagram for a one-step reaction with \(K_{\mathrm{eq}}<1 .\) Label the parts of the diagram corresponding to reactants, products, transition state, \(\Delta G^{\circ},\) and \(\Delta G^{\mp}\). Is \(\Delta G^{\circ}\) positive or negative?

Draw an energy diagram for a reaction with \(K_{\mathrm{eq}}=1 .\) What is the value of \(\Delta G^{\circ}\) in this reaction?

The reaction of hydroxide ion with chloromethane to yield methanol and chloride ion is an example of a general reaction type called a nucleophilic substitution reaction: $$ \mathrm{HO}^{-}+\mathrm{CH}_{3} \mathrm{Cl} \rightleftarrows \mathrm{CH}_{3} \mathrm{OH}+\mathrm{Cl}^{-} $$ The value of \(\Delta H^{\circ}\) for the reaction is \(-75 \mathrm{~kJ} / \mathrm{mol}\), and the value of \(\Delta S^{\circ}\) is \(+54 \mathrm{~J} /(\mathrm{K} \cdot \mathrm{mol}) .\) What is the value of \(\Delta G^{\circ}(\mathrm{in} \mathrm{kJ} / \mathrm{mol})\) at \(298 \mathrm{~K} ?\) Is the reaction exothermic or endothermic? Is it exergonic or endergonic?

Reaction of 2 -methylpropene with \(\mathrm{H}_{3} \mathrm{O}^{+}\) might, in principle, lead to a mixture of two alcohol addition products. Name them, and draw their structures.

Draw the structures of the two carbocation intermediates that might form during the reaction of 2 -methylpropene with \(\mathrm{H}_{3} \mathrm{O}^{+}\) (Problem 6.43 ). We'll see in the next chapter that the stability of carbocations depends on the number of alkyl substituents attached to the positively charged carbon - the more alkyl substituents there are, the more stable the cation. Which of the two carbocation intermediates you drew is more stable?