If electric field is 0 on a Gaussian surface, then the total charge inside this surface is 0. Also, no net flux. Electric Potential is the work done to bring a unit charge from infinity to a point of interest. A capasitor is a device that stores electric potential energy and electric charge.
Water is an excellent solvent for ionic substances such as table salt (sodium chloride, NaCl) precisely because the water molecule is an electric dipole. When dissolved in water, salt dissociates into a positive sodium ion and a negative chlorine ion, which tend to be attracted to the negative and positive ends, respectively, of water molecules; this holds the ions in solution. If water molecules were not electric dipoles, water would be a poor solvent, and almost all of the chemistry that occurs in aqueous solutions would be impossible. This includes all of the biochemi cal reactions that occur in all of the life on earth. In a very real sense, your existence as a living being depends on electric dipoles!