I am wondering what would be the charge density distribution when I bring a sphere of positive charge $Q$ near to the sphere of negative charge? What would be the charge distribution inside the sphere of positive charge $-Q$? I feel that if positively charged sphere is at origin, and we bring negatively charged sphere, then considering that the negatively charged sphere as point charge, it will induce positive charge in the surface of the positively charged sphere, which means that the inner side will be negatively charged.
If they happen to collapse then the total charge will be obviously $0$ but how do I show it mathematically?