Question

How do you calculate enthalpy of hydrogenation?

Answer 1

Hint: We know that the phenomenon of addition of hydrogen to the double bonds that is, in unsaturated compounds to convert them into saturated compounds is known as hydrogenation.

Complete answer:
As we know that enthalpy of hydrogenation is a measure of the stability of carbon-carbon double bonds. It is defined as the enthalpy change when one mole of an unsaturated compound reacts with an excess of hydrogen to become a fully saturated compound. Order of enthalpy of hydrogenation is reversed to the order of stability of alkenes. It means if the compound which is most stable has the lowest heat of hydrogenation and the compound which is least stable has the highest heat of hydrogenation. Enthalpy of hydrogenation is the enthalpy change when one mole of an unsaturated compound reacts with an excess of hydrogen to become a fully saturated compound at atmospheric pressure and room temperature. It is used to compare the stability of pi-bonded molecules.
The amendment in total heat $\left( H \right)$ that happens throughout chemical action chemical action. Used as a groundwork of alkene stability, alkyne stability, conjugation, and aromaticity to match the steadiness of pi-bonded molecules. Once we've m, the mass of your reactants, product’s heat, and the temperature changes from your reaction, we tend to be able to find the reaction total heat. a lot of energy is discharged above the numerical worth of this heat, which implies that the covalent bond was a lot of simply broken down, i.e. the covalent bond was less stable. Therefore, H and alkene stability is reciprocally proportional to modify heat.

Note:
Remember that the amount of energy required to convert the true delocalized structure into a stable structure is known as resonating energy. The resonance energy is the measure of extra stability of a conjugated system compared to the number of isolated double bonds.