Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.
(b)

Show a reaction coordinate diagram for the two processes in Figure 13.41 that rationalizes pathway B as the one that gives the major product.

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In a strongly acidic solution, cyclohexa-1,4-diene tautomerizes to cyclohexa-1,3-diene. Propose a mechanism for this rearrangement, and explain why it is energetically favorable.

The molecular orbital picture of H₂ can be represented by the following diagram. Label σ and σ* on the diagram—that is, which is (a) and which is (b)? Which is lower in energy? Why?

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Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(a)

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(e)

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(e)

Our wayward chemist from Assessment 8.23 suggested the following stepwise mechanism for a hydride shift. Show this mechanism on a reaction coordinate diagram to illustrate why the concerted mechanism is more likely. Justify the picture you have drawn.

Which of the following carbocations would be likely to rearrange? Draw each rearranged structure below.

Molecule I