In a similar experiment, unlabeled 4-butanolide was allowed to stand in an acidic solution in which the water had been labeled with 180. when the lactone was extracted from the solution after four days, it was found to contain 180. which oxygen of the lactone do you think became isotopically labeled?

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Explanation:

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a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.