Question

Acetals are formed from the reaction of two alcohols with a carbonyl under acidic conditions. Acetal formation is faster with 1,2-ethanediol than with two methanol molecules. Choose the factor that explains the difference in reaction rates. A) The reaction with 1,2-ethanediol has a lower ΔH (enthalpy) of reaction. B) The reaction with 1,2-ethanediol has a higher ΔH (enthalpy) of reaction. C) The reaction with 1,2-ethanediol has a more favorable entropy of reaction.

Answer 1

Answer:
The reaction with 1,2-ethanediol has a more favorable entropy of reaction. So the answer is C.

Step-by-step explanation:

Entropy is a measure of the disorder of a system. A more favorable entropy means that the system is more disordered and therefore more likely to react. In the case of the acetal formation reaction, 1,2-ethanediol is a more disordered molecule than two methanol molecules. This is because 1,2-ethanediol has two hydroxyl groups, which can both participate in the reaction. Two methanol molecules, on the other hand, can only provide one hydroxyl group each.

The more disordered molecule is more likely to react because it has more ways to interact with the carbonyl group. In the case of the acetal formation reaction, the carbonyl group is more likely to react with two hydroxyl groups than with one. This is because two hydroxyl groups can form a more stable bond with the carbonyl group than one hydroxyl group.

Therefore, the reaction with 1,2-ethanediol is faster than the reaction with two methanol molecules because it has a more favorable entropy of reaction.