Why is double bond stronger than single bond?
Why does double bond require more space than single bond?
Why is double bond-double bond repulsion more than double bond-single bond and single bond-single bond repulsions?
Are there any other important comparisons between the two?
Single bond - the most durable. For compounds with a single bond characterized by a substitution reaction.
Double bonds can break down - such compounds are more reactive. They are characterized by addition reactions.
Relative to a single bond can be rotated, and relative to the other - it is impossible (steric restrictions).
A single bond is a sigma-bond, sp3 hybridization.
Dual - sigma + pi-bond, sp2-hybridization.
The repulsion exerted by an electron system depends upon the area it occupies. More the area, more is the repulsion.
As the bond pair is formed from the sharing of electrons, it experiences attraction from not one, but two nucleii. On the other hand, the lone pair is attracted by only one nucleus.
So, the bond pair is more localised while the lone pair is spread out and occupies a larger area.
The 'size' here refers not to the size of electrons but to the size and nature of the orbitals these electrons occupy.