Since all four of these are solids, you would mix them with water to get them to dissociate into their respective ions. Ions are charged atoms or molecules that have an imbalance between the nuber of protons, which have positive charges, and electrons, which have negative charges.
For #1: CsOH ---> Cs+ + OH-
For #2: Na2CO3 ---> 2Na+ +CO3-2
For #3: Cu3(PO4)2 ---> 3Cu+2 + 2(PO4)-2
For #4: NH4Cl ---> NH4+1 + Cl-1
Ionic bonds are very powerful bonds. These are formed between an element that is classified as a metal and one that is classified as a nonmetal. Take the bond between sodium and chlorine, which makes sodium chloride, table salt. The melting point of sodium chloride is 801 degrees Celsius! That is quite a contrast when compared to a covalently bonded molecule like sugar, which melts at a much lower temperature.