Question

A bond may be high energy for any of the following reasons except A. products of its cleavage are more resonance stabilized than the original compound. B. the bond is unusually stable, requiring a large energy input to cleave it. C. electrostatic repulsion is relieved when the bond is cleaved. D. a cleavage product may be unstable, tautomerizing to a more stable form. \(\mathbf{E}\). the bond may be strained.

Short answer

A) The products of bond cleavage are more resonance stabilized than the original compound. B) The bond is unusually stable, requiring a large energy input to cleave it. C) Electrostatic repulsion is relieved when the bond is cleaved. D) A cleavage product may be unstable and tautomerize to a more stable form. E) A bond may be strained. Answer: E) A bond may be strained.

Step-by-step solution

Analyze Statement A

In statement A, the products of bond cleavage are more resonance stabilized than the original compound. Resonance stabilization distributes the electron density over a molecule, reducing its energy and making it more stable. If the cleavage products have higher resonance stabilization than the original compound, breaking the bond would result in more stable products, meaning the bond has high energy.

Analyze Statement B

Statement B states that the bond is unusually stable, requiring a large energy input to cleave it. Bonds with high stability (often characterized by low bond length and high bond strength) usually require a greater amount of energy to break. Thus, an unusually stable bond is likely to have high energy.

Analyze Statement C

In statement C, electrostatic repulsion is relieved when the bond is cleaved. This can be a reason for high bond energy since the electrostatic repulsion between the atoms, related to the electrons shared in a bond, may require a higher energy input to overcome it. Breaking the bond would relieve the repulsion, making the system more stable.

Analyze Statement D

According to statement D, a cleavage product may be unstable and tautomerize to a more stable form. Tautomerization is an isomerization process that usually involves the exchange of a proton between two atoms. If a bond cleavage produces an unstable product, the system would naturally favor the more stable tautomer. Consequently, breaking the initial bond would lead to a more stable state, indicating that the bond has high energy.

Analyze Statement E and Choose the Correct Answer

Statement E says that a bond may be strained. Strained bonds usually result from distortions in a molecule's geometry, caused by steric hindrance or other factors. These tensions may make the bond weaker and can be released by breaking the bond. However, the presence of strain does not necessarily imply that the bond will have high energy. Since all other statements discussed why some bonds can have high energy, statement E is the exception and doesn't support that a bond has high energy. Therefore, the correct answer is \(\mathbf{E}\).