Yea I met with my former Chem teacher that I mentioned before and he explained it quite well..
And now I get what you mean about NH3
, thanks for all the help man.. He said that the way it's said in the Lab guide book (some dense NH3
) it means that it doesn't react because it's too little compared to the CaCl2
and it's just there to adjust the pH and neutralize HPO42-
, just as you said..
Thanks again and now I'm writing and completing the report