Nitrates are ionic compounds soluble in water.
Nitrates are salts of the nitric acid.
Potassium nitrate is quite soluble in water, as are all nitrate salts.
Copper salts are salts of copper as chlorides, sulfate, phosphate, nitrate, acetate etc.
You think probable to copper.
Silver nitrate (AgNO3) is a silver salt.
ammonium salts; nitrate salts.
Both of these salts are soluble in water.
Silver nitrate is the most soluble in water of all common silver salts and is generally considered soluble, although it does have a saturation limit.
Ammonium salts of chloride, sulphate and nitrate in aqueous solutions are sufficiently acidic in nature.
Nitrates salts are solids.
For example ammonium salts (nitrate, sulfates) are used as fertilizers in agriculture.