analytical chem cations

TEST FOR GROUP VI (ammonium NH4+)

cation + dil. NaOH → NH3 odor

TEST FOR GROUP I (Silver Ag+ & Lead Pb2+)

• cation + dil. HCI → white ppt → Ag or Pb is present

• hot distilled water → ppt doesnt dissolve

• NH4OH + dil. HNO3 → white ppt

• NH4OH + KI → yellow ppt

TEST FOR GROUP I (Silver Ag+ / Lead Pb2+)

• cation + dil. HCI → white ppt → Ag or Pb is present

• hot distilled water → ppt dissolves

• dil CH3COOH + K2CrO4 → yellow ppt

TEST FOR GROUP II (Cadmium 2+ / Copper 2+)

• cation + dil. H2S → yellow ppt

TEST FOR GROUP II (Cadmium 2+ / Copper 2+)

• cation + dil. H2S → black ppt

• dil. HNO3 + heat → black crust + clear solution

• conc NH4OH → blue solution

• 1- dil CH3COOH + potassium ferrocyanide → reddish brown ppt

• 2- dil HNO3 + KI → white ppt + yellowish brown solution

TEST FOR GROUP III ( Ferric Fe 3+ / Chromium Cr 3+ )

• cation + NH4CI + dil NH4OH → greyish green ppt

• dil NaOH + H2O2 + heat till no bubbles

• dil CH3COOH + lead acetate → yellow ppt

TEST FOR GROUP III ( Ferric Fe 3+ / Chromium Cr 3+ )

• cation + NH4CI + dil NH4OH → brown ppt

• dil HNO3 + heat + NH4SCN → blood red color

TEST FOR GROUP V ( Calcium Ca 2+ / Barium Ba 2+ )

• cation + NH4CI + NH4OH + (NH4)2CO3 → white ppt

• dil CH3COOH + heat → ppt dissolves

• split solution

• 1- K2CrO4 → yellow ppt

TEST FOR GROUP V ( Calcium Ca 2+ / Barium Ba 2+ )

• cation + NH4CI + NH4OH + (NH4)2CO3 → white ppt

• dil CH3COOH + heat → ppt dissolves

• split solution

• 1- K2CrO4 → no observation

• 2- NH4OH + ammonium oxalate → white ppt