GROUP IV and V CATIONS 20 drops of

GROUP IV. and V. CATIONS • • • 20 drops of sample 1 micro spoon NH 4 Cl (10 drops, if liquid) NH 4 OH (until the solution is basic) 20 drops of 1. 5 M (NH 4)2 CO 3 Centrifugate (3000 rpm 4 min) PRECIPITATE (GROUP IV CATIONS) Ba. CO 3, Ca. CO 3, Sr. CO 3 SUPERNATANT (V. GRUP CATIONS) • Add 20 drops of distilled water and centrifugate (3000 rpm 4 min). • Throw away the supernatant. • Add 8 drops of 5 M CH 3 COOH (until the precipitate dissolves completely) GROUP IV CATIONS (Ba+2, Ca+2, Sr+2) • 12 drops of 0. 25 M K 2 Cr. O 4 • Centrifugate (3000 rpm 4 min) PRECIPITATE Ba. Cr. O 4 (sarı) • • • SUPERNATANT Ca 2+, Sr 2+ 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. • NH 4 OH (until the solution is basic) • 12 drops of 1. 5 M (NH 4)2 CO 3 • Centrifugate (3000 rpm 4 min) PRECIPITATE Ca. CO 3, Sr. CO 3 (White) • • Add 20 drops of distilled water and centrifugate (3000 rpm 4 min). Throw away the supernatant. Add 25 drops of 5 M CH 3 COOH (until the precipitate dissolves completely) Heat it until all CO 2 is removed. Ca 2+, Sr 2+ • 20 props of (NH 4)2 SO 4 • 1 -2 crystals of Na 2 S 2 O 3 • Heat to boiling • Filter while it is hot. PRECIPITATE Sr(SO 4) (White) • • • SUPERNATANT Na 2[Ca(SO 4)2] May contain some Sr+2 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. Carmine red flame is observed. • • • 20 drops of 5 M NH 4 OH 1 micro spoon (NH 4)2 C 2 O 4 Heat (to speed up the precipitation) Centrifugate (3000 rpm 4 min). Throw away the supernatant PRECIPITATE Ca. C 2 O 4 (White) • • • 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. Tile red flame is observed.