Lyophilic sols are more stable than lyophobic sols because:

We first recall that a lyophilic sol is one in which the dispersed phase has a definite affinity for the dispersion medium. Because of this affinity, each colloidal particle becomes surrounded by a sheath of solvent molecules. This phenomenon is called solvation (or hydration when the solvent is water).

The solvation sheath behaves like a protective layer. Since the solvent molecules are firmly attached to the surface, two adjoining particles cannot come close enough to aggregate; the intervening solvating layer keeps them apart. Mathematically, we may express the decrease in free energy accompanying solvation as $$\Delta G = \Delta H - T\Delta S < 0,$$ indicating that the process is spontaneous and favours dispersal rather than coagulation.

Because the particles remain well separated, the sol does not settle or precipitate even on standing for a long time. Hence we say that lyophilic sols are intrinsically stable. On the other hand, in a lyophobic sol the particles do not get solvated. They must rely solely on the electrostatic charge present on their surfaces for mutual repulsion. If that charge is removed (for example, by adding an electrolyte), rapid coagulation occurs. This clearly shows that solvation, and not mere charge, is the principal reason for the greater stability of lyophilic sols.

Now we examine the given options. Option A speaks of “no charge,” but we have just argued that stability arises even in the presence or absence of charge provided the particles are solvated. Option B mentions a “positive charge,” which again is not the basic cause. Option D talks of “strong electrostatic repulsion between negatively charged particles,” a feature more typical of lyophobic sols. Only Option C correctly states that the colloidal particles are solvated, and this solvation is the key to their superior stability.

Hence, the correct answer is Option C.