List the four main types of pollution give a very brief explanation of it

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   

It will appear as o2(g) as a reactant 

Ionic compounds dissociate into component ions dissolved into a solution creating substances called "electrolytes".hope my answer has you : )