1. GROUP IV CATIONS GROUP IV. and V. CATIONS (Ba+2, Ca+2, Sr+2)
20 drops of sample
1 micro spoon NH4Cl (10 drops, if liquid)
NH4OH (until the solution is basic)
20 drops of 1.5 M (NH4)2CO3
Centrifugate (3000 rpm 4 min)
GROUP IV CATIONS
(Ba+2, Ca+2, Sr+2)
12 drops of 0.25 M K2CrO4
SUPERNATANT
Ca2+, Sr2+
PRECIPITATE
BaCrO4 (sarı)
Add 20 drops of distilled water and centrifugate (3000 rpm 4 min).
Throw away the supernatant.
Dissolve the precipitate in concentrated HCl.
Burn it on platinium wire.
Green flame is observed.
12 drops of 1.5 M (NH4)2CO3
CaCO3, SrCO3 (White)
Add 25 drops of 5 M CH3COOH (until the precipitate dissolves completely)
Heat it until all CO2 is removed.
20 props of (NH4)2SO4
1-2 crystals of Na2S2O3
Heat to boiling
Filter while it is hot.
Na2[Ca(SO4)2]
May contain some Sr+2
20 drops of 5 M NH4OH
1 micro spoon (NH4)2C2O4
Heat (to speed up the precipitation)
Centrifugate (3000 rpm 4 min).
Throw away the supernatant
CaC2O4 (White)
Tile red flame is observed.
Sr(SO4) (White)
Carmine red flame is observed.
(GROUP IV CATIONS)
BaCO3, CaCO3, SrCO3
(V. GRUP CATIONS)
Add 8 drops of 5 M CH3COOH (until the precipitate dissolves completely)