Statement - I : An isolated conductor can not have a large capacitance.
Statement - II : When a conductor holds a large amount of charge, a breakdown occurs in the insulation of the surrounding medium.

The capacitance of a conductor is given by C = Q / V, where V is potential of the conductor. In the case of a neutral conductor placed nearer to the charged conductor, then the potential of the charged conductor reduces and its capacity increases. But, in the case of isolated conductor, its capacitance can't be increased to high since its potential is constant and can't be reduced due to absence of another conductor.