Zinc is a chemical element with symbol Zn. It is found in various salts like zinc chloride and zinc sulphate as Zn (II) ion. Zinc ions are precipitated as their sulphides by passing hydrogen sulphide gas through their solution. Zinc ions react with sodium hydroxide to form white precipitate of zinc hydroxide and also react with potassium ferrocyanide to form white or bluish white precipitate of zinc ferrocyanide.
This video explains how to test for the presence of zinc ion in a given salt.