CATIONS I AND II

Question 1

group 1 cations

Answer 1

Ag+
Hg2 2+
Pb 2+

insoluble chlorides

Question 2

group 2 cations

Answer 2

Hg 2+
Pb 2+
Cu 2+

Bi 3+
Cd 2+
As 3+

Sb 3+
Sn 4+

insoluble sulphides in acidic medium

Question 3

group 3 cations

Answer 3

Al 3+
Fe 3+
Co 2+

Ni 2+
Cr 3+
Zn 2+

Mn 2+

insoluble sulfides or hydroxides in alkaline medium

Question 4

• The three cations form insoluble chloride with _________
• When 6M of HCl is added to the solution, white precipitates of ______, ______, ______ are formed
• Other metallic cations remain in solution

Answer 4

GROUP 1 CATIONS

• hydrochloric acid
• AgCl, Hg2Cl2 and PbCl2

Question 5

CATIONS 1

1. Lead (I) or Plumbous [Pb+1]
2. Silver or Argentum [Ag+1]
3. Mercury (I) or Mercurous [Hg+1]

Answer 5

1. CR: K2CrO4
   PR: yellow ppt
   reagent responsible for the result: PbCrO4
2. CR: HNO3
   PR: white ppt
   reagent responsible for the result: AgCl
3. CR: SnCl2
   PR: white/gray ppt
   reagent responsible for the result: Hg2Cl2 or Hg

Question 6

1. Identification of Lead Ion
2. Identification of Silver
3. Identification of Mercurous

Answer 6

1. Pb++ + CrO4 —> PbCrO4
2. Ag(NH3)2+ + Cl- + 2H3O —> AgCl + 2NH4 + 2H2O
3. HgCl2 + SnCl4 —> Hg2Cl2 + SnCl6-

Question 7

• Composed of 8 cations which precipitates as sulfides
• Sulfides of ______, ______, ______, ______, ______, ______, ______, ______
• ______, ______, ______, ______, ______ exhibits basic properties —> insoluble residue —> Group II A
• ______, ______, ______, ______ exhibits acidic properties —> soluble with KOH —> Group II B

Answer 7

GROUP 2 CATIONS

• cupric, mercuric, plumbic, bismuth, cadmium, arsenic, antimony, and tin ions
• HgS, CuS, Bi2S2, PbS, CdS
• As2S3, SnS3, SnS2, SbS3

Question 8

Analysis of group II ions

Answer 8

Three major steps

1. the group is precipitated with sulfides then subdivided into subgroups by action of KOH
2. analysis of group IIA
3. analysis of group IIB

Question 9

CATIONS IIA

Answer 9

1. mercuric ion [Hg+2]
2. cupric ion [Cu+2]
3. bismuth [Bi+3]
4. lead ion [Pb+2]
5. Cadmium [Cd+2]

Question 10

CATIONS IIA

1. Mercury (II) or Mercuric [Hg+2]
2. Copper (II) or Cupric or Cuprum [Cu+2]
3. Bismuth [Bi+3]
4. Lead (II) or Plumbic [Pb+2]
5. Cadmium [Cd+2]

Answer 10

1. CR: SnCl2
   PR: white ppt
   reagent responsible for the result: Hg2Cl2
2. CR: NH3 or NH4OH
   PR: deep blue color
   reagent responsible for the result: Cu(CN)2
3. CR: Sn(OH)3
   PR: black ppt
   reagent responsible for the result: Bi
4. CR: CrO4
   PR: yellow ppt
   reagent responsible for the result: PbCrO4
5. CR: H2S
   PR: yellow ppt
   reagent responsible for the result: CdS

Question 11

1. Identification of Mercury II Ion
2. Identification of Copper II ion
3. Identification of Bismuth ion
4. Identification of Lead ion
5. Identification of Cadmium ion

Answer 11

1. HgCl4 + SnCl4 —> Hg2Cl2 + SnCl6 + 4Cl
2. 2Cu(NH3)4CN —> 2Cu(CN)4 + 8NH3
3. 2Bi(OH)3 + 3Sn(OH)3 +3 + 2Bi + 3Sn(OH)6
4. Pb(C2H3O2)3 + CrO4 —> PbCrO4 + 2C2H3O2
5. Cd(CN)4 + H2S —> CdS + 2HCN + 2CN

Question 12

cation IIB ions

Answer 12

1. Arsenic [As+5]
2. Antimony or Stibium [Sb+3]
3. Tin II or Stannous [Sn+2]

Question 13

cation IIB

1. Arsenic [As+5]
2. Antimony or Stibium [Sb+3]
3. Tin (II) or Stannous [Sn+2]

Answer 13

1. CR: AgNO3
   PR: reddish brown ppt
   reagent responsible for the result: Ag3AsO4
2. CR: NaOCl
   PR: black deposit
   reagent responsible for the result: Sb+3
3. CR: HgCl2
   PR: white/gray ppt
   reagent responsible for the result: Hg2Cl2 or SnCl6

Question 14

1. Identification of arsenic ion
2. Identification of antimony ion
3. Identification of tin ion

Answer 14

1. H2AsO4 + 2OH- —> AsO4 +3 + 2H2O
2. 2SbCl6 + 3Sn —> Sb + 3SnCl4-
3. SnCl4 + 2HgCl2 —> Hg2Cl2 + SnCl6