AnaChem Lab

• What are the Group 1 cations

  Ag+, Pb2+, Hg+
• what is added to the unknown solution to confirm if there is presence of Pb+2?

  Potassium Chromate (0.2M K2CrO4)
• What confirms the presence of lead ion (Pb+2)?

  yellow precipitate
• what is the precipitating agent for group 1 cations?

  6M HCl
• what confirms the presence of group 1 cations?

  white precipitate
• What confirms the presence of Mercury (Hg+)? Blackening of the PPT or gray PPT
• What is added to unknown to determine if there is a presence of Hg+? 6M NH4OH (ammonium hydroxide)
• What confirms the presence of silver ion (Ag+)? White precipitate/Pale yellow precipitate
• What is added to unknown to determine the presence of silver? HNO3 (nitric acid)/KI solution (potassium iodine solution)
• Group IIA (copper group) that is insoluble in KOH and HNO3: Bi+3, Cd+2, Pb+2, Cu+2, Hg+2
• Group IIB (arsenic group) that is soluble in KOH and HNO3: As+3, As+5,+Sb+3,Sb+5, Sn+2, Sn+4
• Precipitating agent of group II: H2S
• What added to separate the 2 groups (arsenic and copper group) of Group II cations? KOH solution
• What chemical is used to make H2S? 1M thioacetamide (C2H2NS)
• What confirms the presence of group II cations? Dark precipitate or colored precipitate
• If there is no precipitate (white or pale yellow precipitate), is the group II cations present or absent? Absent
• The ____, contains ions from copper group. Precipitate/residue
• The ____, contains ions from arsenic group. Supernatant liquid
• State the chemicals that is added to separate and test the bismuth and copper ion. 5M NH4NO3 (ammonium nitrate), 6M HNO3 (nitric acid), 15 M NH4OH (ammonium hydroxide)
• What indicates the presence of copper? Deep blue colored solution
• What indicates the presence of bismuth? White precipitate
• In confirmatory test of copper, what is added? 6M acetic acid (CH3COOH) and 2M K4Fe(CN)6 (potassium ferrocyanide)
• In confirmatory test of copper what is the color of precipitate? Red-brown precipitate
• What is added to the solution labeled as As? Concentrated HCl
• what indicates the presence of Sb+3 (antimony)?

  red-orange precipitate
• What confirms the presence of Sn+2 (tin)?

  white precipitate or grey precipitate
• what is added to clear liquid in doing the test for Sn+2?

  0.1 M HgCl2 (Mercury II chloride)
• for another test of Sn+2, what is added to the second solution?

  ammonium molybdate (NH4)2MoO4
• for another test of Sn+2, what is the positive result for Sn+2?

  blue color
• ___ will be added to the unknown solution (for group 3) until its basic
• ___ will be added to the unknown solution (for group 3) until its basic, and then ___ is added.

  NH3 (ammonia) or NaOH (Sodium Hydroxide) ; (NH4)2S (ammonium sulfide)
• what divalent metal ions precipitate as their sulfides in group 3?

  Co+2, Fe+2, Mn+2, Ni+2, Zn+2
• trivalent metal ions that precipitate as hydroxides in group 3

  Al(OH)3 and Cr(OH)3
• Group IIIA (aluminum group)

  Al+3, Cr+3, Zn+2
• Group IIIB (Iron group)

  Fe+2, Fe+3, Co+2, Ni+2, Mn+2
• To the unknown solution add ____, ____ until basic.(group 3)

  NH4Cl (ammonium chloride) ; NH4OH (ammonium hydroxide)
• what will be used to test aluminum group?

  Precipitate
• what is used for complete precipitation in precipitating the aluminum group?

  1M thioacetamide (C2H5NS)
• Add ___ and boil until no bubbles of oxygen are no longer evolved. (group 3) 3% H2O2
• Precipitate is for ___, while supernatant liquid is for ___. (group3-separation of fe and al group)

  Fe group ; Al group