The anions it could be are, NH4, Li, Na, K, Mg, Ca, Ba, Al, Fe, Cu, Ag, Zn or Pb

The first step is to add HCl

if it doesn’t have a precipitate then that means it is NH4, Li, Na, K, Mg, Ca, Ba, Al, Fe, Cu or Zn. We will call this section one

If there is a precipitate, it is either Pb or Ag. This will be referred to as Section 2

The next step for section one is to add H2SO4

if there is a precipitate it is Ba or Ca. If it is milky you know it is Ca but if it is a solid precipitate it could be either. This is called section three

If there is no precipitate then it must be NH4, Li, Na, K, Mg, Al, Fe, Cu or Zn this is section four

The last step for section two is to use an Iodide as it is bright yellow for Pb and milky for Ag

The next step for section three is to add potassium chromate. If it is a solute then it is Ba if it is isn’t it is Ca.

As for section four, use a carbonate (CO3)

if there is a precipitate, it is NH4, Li, Na or K

if there is no precipitate it is Mg, Al, Fe, Cu or Zn