What is the order of heat of hydrogenation of the following compounds:




A. 2 > 3 > 5 > 1 > 4B. 2 > 3 > 5 > 4 > 1C. 1 > 2 > 3 > 5 > 4D. 5 > 3 > 2 > 4 > 1

The order of heat of hydrogenation of compounds is determined by the stability of the resulting alkene or cycloalkane after hydrogenation. More stable compounds require less energy to hydrogenate because they have lower potential energy.

In general, the stability of alkenes follows the order:

Cycloalkenes are more stable than straight-chain alkenes of the same size.
Alkenes with more substituted (branched) double bonds are more stable than less substituted ones.
Trans isomers are generally more stable than cis isomers.
Now, let's analyze the given compounds:

Compound 1 is a cycloalkene with a trans double bond.
Compound 2 is a cycloalkene with a cis double bond.
Compound 3 is a straight-chain alkene.
Compound 4 is a straight-chain alkene with a cis double bond.
Compound 5 is a straight-chain alkene with a trans double bond.
Based on the stability principles mentioned above, we can order them:

Compound 1 (cycloalkene with trans double bond)
Compound 2 (cycloalkene with cis double bond)
Compound 3 (straight-chain alkene)
Compound 4 (straight-chain alkene with cis double bond)
Compound 5 (straight-chain alkene with trans double bond)
So, the correct order of heat of hydrogenation for these compounds is:

C. 1 > 2 > 3 > 5 > 4