Explain the relationship between heat of hydrogenation and stability of a pi system and explain why the instability of electrons in a pi MO directly relates to the number of nodes the orbital possesses.
ANSWER:-
Heat of hydrogenation of alkenes is a measure of the stability of carbon-carbon double bonds. All else being the same, the smaller the numerical value of heat of hydrogenation of an alkene, the more stable the double bond therein
he energy of an atomic orbital mainly depends on the quantum number nn:
En∝−Z/n2
where ZZ is the atomic charge. So higher nn means more nodes and higher (less negative) energy, which is in agreement with the general node rule for nn. This also agrees with the quantum numbers ll and mm, as they neither change the orbital energy (it only depends on nn) nor the total number of nodes. (This is considering an atom with one electron only)
Explain the relationship between heat of hydrogenation and stability of a pi system and explain why...