Which of the following explains why heats of hydrogenation cannot be used to determine the relative stability of compounds A and B below?
A)Compound A is trisubstituted while compound B is monosubstituted.
B)Compound A has E configuration while compound B has no E/Z configuration.
C)Both compounds A and B have no E/Z configurations.
D)Hydrogenation of A and B give different alkanes.

Question

Which of the following explains why heats of hydrogenation cannot be used to determine the relative stability of compounds A and B below? 
A)Compound A is trisubstituted while compound B is monosubstituted. 
B)Compound A has E configuration while compound B has no E/Z configuration. 
C)Both compounds A and B have no E/Z configurations. 
D)Hydrogenation of A and B give different alkanes.

Quizplus · Accepted Answer

Heats of hydrogenation are based on the enthalpy change of hydrogenation, which is determined by the number of pi bonds broken and sigma bonds formed. Since compounds A and B give different alkanes upon hydrogenation, the heat of hydrogenation values cannot be used to determine their relative stability. The other choices do not impact the use of heats of hydrogenation to determine stability.

Which of the Following Explains Why Heats of Hydrogenation Cannot