Group III Cations Schematic Diagram PDF

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Name: Condrillon, Choren G. Date: February 4, 2 021Schematic Diagram for the Separation of Group 3 CationsSolution Containing Group III Cations:Al+3, Cr+3, Zn+2, Fe+2, Fe+3, Mn+2, Co+2, Ni+Add 1mL of 5M NH 4 Cl, 15 M NH 4 OH until basic plus 5 dropsin excess. Add 10 drops of 1M thioacetamide (C 2 H ...

Description

Name: Condrillon, Choren G.

Date: February 4, 2021

Schematic Diagram for the Separation of Group 3 Cations Solution Containing Group III Cations: Al+3, Cr+3, Zn+2, Fe+2, Fe+3, Mn+2, Co+2, Ni+2 Add 1mL of 5M NH4Cl, 15 M NH4OH until basic plus 5 drops in excess. Add 10 drops of 1M thioacetamide (C2H5NS), water bath for 7 to 10 minutes, then centrifuge and decant.

Precipitate (A-1)

Supernatant Cations of later groups

Ions of the aluminium-iron group

For complete precipitation, add 5 drops of thioacetamide and heat for 5 to 10 mins. Return the suspension with precipitate (A-1) and centrifuge. Repeat until precipitation is complete.

Add 10 drops of 6M HNO3. Warm tube and agitate the suspension. Pour solution into evaporating dish. Remove globules of sulfur with the tip of glass rod. Evaporate the solution to 2 or 3 drops. Add 10 drops of 16M HNO3 and 0.2g of potassium chlorate crystals. Evaporate to 3 drops. Add another 16M HNO3 and 0.1g of potassium chlorate and evaporate to 3 or 4 drops (Add HNO3 if the evaporation is carried too far). Dilute with water to 2mL.

Black stain precipitate present in evaporating dish

Absence of Mn+2, no black stain

Transfer suspension to test tube and centrifuge and decant. Rinse with 1 mL of water, pour the washing into the test tube with precipitate, agitate, centrifuge and decant the washing into the solution (A-B-1).

Treat solution according to A-B-1

SUPERNATANT

A-B-1

Washed precipitate

add 6M NaOH until basic, then add 8 drops in excess. add 5 drops of 3% H2O2 and boil until no more bubbles of oxygen evolved, then centrifuge and filter.

Add 10 drops of 6M HNO3. Warm. Add a drop of 3% H2O2. (Add more H2O2 to dissolve precipitate if necessary). Pour solution to stained evaporating dish. Warm (if necessary) to dissolve the black stain, add a drop or 2 of H 2O2. If black or brown precipitate begins to form, discontinue the evaporation Add 10 drops of 6M HNO3 Add 1mL of water. Add solid sodium bismuthate (NaBiO3) a pinch at a time until solid remains undissolved.

FILTRATE

PRECIPITATE Wash 2 mL of water, centrifuge, and discard the washings. Dissolve by warming with 10 drops of 6M HCl .

Containing iron group (A-2)

Pink or purple color indicated the presence of Mn+2 ion.

Brown or black residue, insoluble in the HCl solution is MnO2

Dilute 2mL with water then add 6M NH4OH until alkaline, then 5 drops in excess.

Positive test for Mn+2, discard this residue. Negative test, treat the dark residue: Add 10 drops of 6M HNO3. Add 1mL of water. Add solid sodium bismuthate (NaBiO3) a pinch at a time until solid remains undissolved.

precipitate

No precipitates

Precipitate forms Centrifuge and decant

supernatant

precipitate

Presence of Ferric ion Wash with 1mL of water, entrifuge, and discard the ashings. issolve residue in 5 drops f 6M HCl, dilute to 2mL, nd add 5 drops of 1M SCN solution.

Deep red solution, confirms presence of of Fe+3

Test for Ni+2 (A -4)

Test for CO+2 (A-3) add 6M acetic acid until acidic then add 3 drops in excess. add 1 mL of 6M KNO2 then warm and stand for a few minutes.

Yellow or olive colored precipitate indicates the presence of Co+2 *If no precipitate is observed, add 3 to

add 6 drops of 1% dimethylglyoxime solution

Red or pink precipitate, confirms presence of Ni+2

Containing Aluminum group(B-1)

Brown solution indicates presence of Cobalt add 10 drops of 1% dimethylglyoxime, centrifuge, and decant

Wash with 1 mL of hot water, centrifuge, and discard washings. Repeat once. Add 6M HNO3 drop by drop until dissolves. Agitate after each drop. Once dissolved, add 2 drops of aluminum reagent. Add 6M NH4OH drop by drop until basic to litmus and precipitate reforms.

Pink/red precipitate in a colorless solution confirms the presence of Al+3

Add 6M HNO3 until acidic then add 6M NH4OH drop by drop until basic. Add 5 drops of NH4OH and water bath in 5 mins. Centrifuge and decant.

supernatant

Test for Cr+3 (B-2)...