Systematic analysis of of I-IV analytical groups cations mix

Preliminary tests.

1. Determination NH₄ ⁺ (with alkalis by heating).

2. Determination Hg₂^{2 +} (with metal copper).

3. Determination Сr^{3 +} (oxidation in the basic medium and formation peroxichromatic acids).

4. Determination Al^{3 +}(drop way with alizarine).

5. Determination Nа ⁺ (with Potassium hexahydrocsoantimonat (V), you do it after determination of NH₄ ⁺ ions, if there aren’t this ions, than you do preliminary test).

6. Determination As^{III, V} (restoration to арсина).

7. Determination Sn^{2 +} (reaction with Bi (NO₃) ₃ in the alkaline environment).

Regular course of the analysis

1.To a solution which contains a mix катионов І - ІV analytical groups add 2 mol/l a solution хлоридной acids. In a precipitate chlorides катионов ІІ analytical group drop out, and in a solution there are ions І, ІІІ, ІV analytical groups.

Solution 1 Precipitate 1

NH₄ ⁺, Na ⁺, K ⁺, Ca^{2 +}, Sr^{2 +}, Ba^{2 +}, AgCl, Hg₂Cl₂, PbCl₂

Al^{3 +}, Zn^{2 +}, Cr^{3 +}, As^III, As (V), Sn^II, Sn^IV

2. Precipitate 1 wash out the distilled water and центрифугируют, rejecting washing waters. A precipitate analyze under the analysis scheme катионов ІІ analytical group (employment 2 see).

3. The solution 1 is processed by 2 mol/l a solution of sulphatic acid, adding quantity of ethanol equal behind volume. In a precipitate sulphates катионов ІІІ analytical group drop out, and in a solution there are ions І and ІV analytical groups.

Solution 2 Precipitate 2

NH₄ ⁺, Na ⁺, K ⁺, Al^{3 +}, Zn^{2 +}, Cr^{3 +}, CaSO₄, SrSO₄, BaSO₄

As^III, As (V), Sn^II, Sn^IV

4. Precipitate 2 wash out the distilled water, mix and центрифугируют, rejecting washing waters. A precipitate analyze under the analysis scheme катионов ІІІ analytical group (employment 2 see).

5.In separate portions of a solution 2 find out a fractional method катионы Zn^{2 +}, As^III, As (V), Sn^II, Sn^IV. Ions NH₄ ⁺, Na ⁺, Al^{3 +}, Cr^{3 +} have been revealed in preliminary test, therefore the solution 2 can to be investigated on presence of these ions.

At desire a solution 2 analyze under the analysis scheme катионов ІV analytical group (see above).

6.Part of a solution 2 process crystal Sodium a carbonate. Thereof катионы ІV analytical group (Al^{3 +}, Zn^{2 +}, Cr^{3 +}, Sn^II, Sn^IV) are besieged in a kind hydroxideов or гидроксосолей, and in a solution remained катионы І analytical group with ions As^III, As (V).

Solution 3 Precipitate 3

NH₄ ⁺, Na ⁺, K ⁺, As^III, As (V) Al (IT) ₃, Zn (IT) _{­ 2}, Cr (IT) ₃, Sn (IT) ₂, Sn (IT) ₄

Precipitate 3 reject and do not analyze.

7.In a solution 3 after removal of ions NH₄ ⁺ find out ions K ⁺ behind reaction with Na₃ [Co (NO₂) ₆].

For research it is impossible to take all sample, and it is necessary to take only its part as during the analysis losses and, in case of use of all test are possible, all analysis will be lost.

The scheme of the analysis of a mix катионов І - ІV groups

		NH4 + with alkali

Al3 +with alizarine

Solution І, ІІІ, НСl a solution

ІV groups І - І groups

Deposit катионов ІІ groups

AsIII, V with Zn + HCl

H2SO4, C2H5OH

Deposit катионов ІV groups