posted by Reen .
a few drops of NaOH are added to a sample of the unknown. A blue precipitate appears. Next, approximately 1mL of ammonia, NH3, is added. The precipitate dissolves, but the solution remains blue. Which ion is present. Explain
If the color of the original sample was NOT blue, then the ppt with NaOH probably is Cu(OH)2 and the addition of ammonia produces a dark blue solution of Cu(NH3)4^+2. (I don't see a DARK BLUE solution mentioned so I may be taking something for granted here.)