Marcha De Cationes

Cation’s analysis

Ana María Bejarano Acero 20101150003, Tatiana Forero Rodríguez 20101150021, Cindy Ortíz. 201021500411
Álvaro Jiménez2
Alejandro Patarroyo3

Abstract: The following report aims to show the results of the analysis of a sample containing a certain amount of cations, this through a process called systematic separation and identification of cations.
Key words: Cation,precipitation, solution.

Theorical Frame

Karl Remigis Fresenius (1818-1897)

With the consolidation of the modern conception of chemical composition in the late eighteenth century, along with the increasing importance of quantitative studies of chemical processes led to the emergence of a set of knowledge that gave rise to analytical chemistry.
It was characterized by the care and precisionwith which their analytical procedures were performed. Many of his methods, such as the quantitative determination of lithium, manganese and nickel, acid - phosphoric acid, boric-were employed for decades. In conducting his research had to synthesize their own reagents.
To improve the accuracy of the methods of precipitation, he conducted numerous studies about solubility and developed detailedmethods for the analysis of water. Explained a method based on separation of cations in groups.
 
Method "MSA" (Analytical March)

The given sample (problem) have for identification 16 cations that are on our march into 4 groups of the most common, to apply the method, it needs to be totally dissolved to have their components (cations-anions) these are determined by a series of unit operationswhich form complexes or salts of unique features such as color.

It may have general reagents can react with most cations and reagents that are directly applied to find the specific cation, in the march we can find the masking that is when you have two cations with very similar characteristics, in this case is that add reagents to help unmask.

Reaction equations

March Group 1
1.Obtaining precipitates.

* Ag+(ac) + NH4Cl(ac) AgCl(S) (white) + NH3(ac)
* Hg22+(ac) + NH4Cl(ac) Hg2Cl2(s) (white) +NH3(ac)
* Bi3+(ac) + NH4Cl(ac) )BiOCl(s) (white) + NH4(ac)
(Not obtained)

March Group 2
1. Obtaining precipitates.
∆
* Al+3(ac) + NH3(ac)+ H2OAl(OH)3(s) (white) + NH3(ac)
* Fe3+(ac)+NH3(ac)+H2OFe(OH)3(s) (red brown) + NH3(ac) (not obtained)

2.Aluminum separation

* Al(OH)-3(ac)+NH3(ac)+NaOH(ac)Na+ [Al(OH)4)]-(ac) (transparent solution)

* Fe(OH)3(ac) +NaOH Fe(OH)-3 + NaOH

3. Aluminum confirmation (Positive)

* [Al(OH)4)]-(ac) + Aluminón + NH3(ac) [Al(C22H23N3O9)3](s) (red) Final Test.

March Group 3.

1. Obtaining precipitates.

Ba2+ (ac) +HPO4-2(ac) NH4 Ba3 (PO4)2↓(S)
Ca2+ (ac) +HPO4-2(ac) NH4Ca3 (PO4)2↓(ac) P3
Mg2+ (ac) +HPO4-2(ac )NH4 MgNH4PO4 ↓(ac)

2. Zinc test (Negative)

* Zn2+(ac) +HPO4-2(ac) → Zn2+(ac)+HPO4-2(ac) CH3COOH ZnNH4PO4 ↓ (S) (not obtained)

3. Barium test (Negative)

* Ba3(PO4)2(S) HCl Ba2+(ac) + PO4-3(ac)
* Ca3(PO4)2(S) HCl Ca2+(ac) + PO4-3(ac)
* MgNH4PO4(S) HCl Mg2+(ac) + PO4-3(ac)

*Ca2+(ac) +(NH4)2SO4 HCL Ca(SO4)(ac)+ (NH4) PO4
* Mg2+(ac) +(NH4)2SO4 HCL Mg(SO4)(ac)+ (NH4) PO4
* Ba2+ (ac) +(NH4)2SO4 HCL Ba(SO4) ↓ (s) + (NH4) PO4 (not obtained)

4. Calcium test (Positive)

* 1/3 Ca2+(ac) + C8H8N6O6(ac) NH3
[Ca (C8H8N6O6)]- (ac) (Orange) + NH4+(ac) Obtained
* 2/3Mg2+(ac) + (NH4)C2O4(ac)+ COOHNa(l)→ CaC2O4(s)↓ + Mg2+(ac) +COOHNH4(ac)+ Na+(ac)
Precipitate obtained

5. Magnesium test (Negative)

March Group 4

1. Ni2+ Cation identification.

* Ni+2 (ac) +C4H8N2O2(ac) CH3COOH [Ni(C4H8N2O2)] (S) + H2O (Not Obtained)
* Ni+2 (ac) + NaOH(ac)→Ni(oH)2↓(s)+ Na+X
(Not Obtained)

2. Cu2+ Cation Identification

* Cu+2(ac)+ Fe(CN)6 HCL Cu(CN)2(S) + Fe+2 X
(Not obtained)

3. Co2+ Cation...