Four compounds are shown. These compounds react more quickly, or they react with more favo...

Four compounds are shown. These compounds react more quickly, or they react with more favorable equilibrium constants, than similar compounds with less conjugated systems. In each case, explain the enhanced reactivity.

(a)  is more basic than

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(b)  ionizes more readily than

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(c)  dehydrates under much milder conditions than

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(d) Umbelliferone (7-hydroxycoumarin) is a common plant product that is used in sunscreen lotions.  is more acidic than