A charge of -72 mC is needed to lift the mass off the table.
As it lifts off the table, the mass will move up toward the charge holding it.
The mass can be lifted off in equilibrium with the second charge as long as there are no other forces acting on it. This is because electric force is repulsive with an object of the same charge and attractive with an object of opposite charge. This means that when the two charges are of opposite sign they will attract each other and they may be able to find an equilibrium point