Your question is not clear: the mass of products is equal to the mass reactants.
Zinc Hydroxide-Colorless, water-soluble crystals that decompose at 125°C; used as a chemical intermediate and in rubber compounding and surgical dressings.
The formation of the soluble Zn(OH)4- ion (tetrahydroxidozincate ion)
Zinc hydroxide. It is base
Zn(OH)2 is an amphoteric compound (dual nature), with acids it behaves as a base and with bases (alkali) as an acid, Zn(OH)2 + 2HCl = ZnCl2 + 2H2O , Zn(OH)2 + 2NaOH = Na2ZnO2 + 2H2O
Zn(OH)2, or zinc hydroxide, is used as a mordant for dies. It is used as an intermediate in the production of pesticides. It is used in lotions with zinc oxide. It is even used in some batteries and rubber goods.