Which forces involve nonpolar molecules

The forces that involve non-polar molecules is called london dispersion forces. Non-polar molecules have bonds in which the electrons are shared equally between the participating atoms. Polar bonds are joined by dipole-dipole forces, on the other hand.

Ch4 is nonpolar and insoluble in water. since all of the hydrogen atoms are evenly spread around the carbon atom even through the c h bond is polar all the poles cancel each other out.