Qualitative Analysis of Group I Cations: Precipitation and Separation of Group I lons Nam Partner’s Name of any) Lab Section MWITH THE Advance Study Assignment 1. The reagent (chemical substance used) to precipitate the all the cations of Group _(symbol and molarity 2. Why do we add an additional drop of the precipitating to the Group I precipitate formed? 3. When we centrifuge why must we use a blank test tube (containing an equal volume of water) on the opposite side of the test tube containing our precipitate? 4. The precipitating reagent was added to a 1 mL sample of the known solution in a test tube. The precipitate that formed was centrifuged and the solution above the precipitate (supernatant) was discarded. Why can we discard supernatant in this step of the experiment? 5. Approximately two mL of dH 0 was added to the precipitate in the test tube above and heated in a boiling water bath, centrifuged and the solution again decanted. It was noticed that the amount of precipitate present was less than what was there before it was heated. What happened to the precipitate? 6. To the white precipitate remaining in the test tube in 5 above, – mL of 6 MNH, was added A color change occurred. What did this mean? 7. How do we confirm the presence or absence of silver ions, Ag?