Problem related to two conductors in contact

[gracy]

are they going to get as far from each other as possible?

They are going to get as far from each other as possible.
But why on the outer surface of the spherical shell not on the small conductor?

 

[Chestermiller]

They are going to get as far from each other as possible.
But why on the outer surface of the spherical shell not on the small conductor?

Because they can migrate from the small conductor to the spherical shell, and thereby get further apart.