How do you know if you have a balanced equation?

If each side of the equation has the same number of atoms of a given element, that element is balanced.

Cr(oh)3 -> cr(3+) + 3oh-

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf