File Name: qualitative analysis of cations and anions .zip
To determine the cation which can be found in the analite 2. To determine the anion which can be found in the analite V. Basic Theory A. Qualitative Analysis Chemical analysis can be divided into two categories; qualitative analysis what is present and quantitative analysis how much is present. Qualitative ana- lysis involves the detection of elements that are found in an organic compound. Qualitative analysis can only detect the presence of elements in the compound but cannot determine the percentage or amount of them in the compound.
For example; carbon and hydrogen are detected with the help of Liebig s method. Some other common elements which can be determined are oxygen, halogen, sulphur, nitrogen, halogens, sulphur and phosphorus.
Qualitative analysis is a type of chemical analysis which is used to separate and detect cation and anions in a sample substance.
The chemical properties of an unknown substance are determined in the qualitative analysis procedure by the reaction between the unknown substance and suitable reagents. The qualitative analysis is used for the identification of a simple salt or the identification of various cations present in a solution. Cations Cations are divided into five groups. A specific reagent for each group is used for their separation from the solution.
This separation is done in a particular se- quence because some ions of prior groups can also react with the reagent of later groups. The qualitative analysis of cations depends on the solubility products of the ions. The cations get precipitated on the optimum needed concentration and easily detected.
The other groups will remain in solution thus allowing the Group I chloride precipitates to be removed and further tested. Colour detection test is not suitable for their chlorides because all are white solid compounds. The analysing of group is done by adding the respective salt into water and follow it with dilute HCl. This results in a white precipitate in which NH4OH is added.
The tests are conducted in presence of dilute HCl to keep the S 2- ion concen- tration at a minimum level. This round of tests helps only in second 2nd gro- up cations precipitation. The cations precipitation of the 4th group if present in the solution might occur in the absence of dilute HCl which can give wrong results. The use of sulphuric acid and nitric acid can cause to the precipitation of the 4th group cations and formation of colloidal sulphur respectively. This group is determined by the addition of the respective salt in water and then adding dilute HCl and then follow it by adding H 2S.
However they form precipitates with ammonium sulphides NH4 2S in neutral or ammonical medium. They precipitate with ammonium carbonate NH 4 CO3 in the pre- sence of ammonium chloride in neutral medium. The result of experiment and the presence of the respective ions are shown in the table below.
It can be identified by special reaction or by flame test. Magnesium cation showing similar reaction with group IV cations. Sodium and potassium ion are from group IA Alkaline , and they have similarity. Both of them are big enough, colourless, can not reduced in solution state, so it can not react with water. Anions The methods available for the detection of anions are not as systematic as those which have been described above for cations.
No really satisfactory scheme has yet been proposed which permits the separation of the common anions into major groups, and the subsequent unequivocal separation of each group into its independent constituents; however, it is possible to detect anions individually in most cases, after perhaps a stage separation. It is advantageous to remove all heavy metals from the sample by extracting the anions through boiling with sodium carbonate solution; heavy metal ions are precipitated out in the form of carbonates, while the anions remain in solution accompanied by sodium ions.
The following scheme of classification of anions has been found to work well in practice; anions are divided into four groups on the basis of their reactions with di- lute hydrochloric acid and of the differences of solubilities of their barium and sil- ver salts.
However, they form precipitates with silver ions in dilute nitric acid medium. To identify nitrate ion can be done by brown ring test which can be done by adding concentrate H2S04 and then adding saturated FeSO4 little by little through the tube wall. Tools and Material A. Tools B. Materials 1. Test tube 1. Sample NH4NO3 2. Pipettes 2. NaOH solution 3. Litmus paper 3. Saturated Na2CO3 4. Test tube rack 4. Concentrated H2SO4 5. Filter paper 5. Saturated FeSO4 6.
Tripod 7. Funnel 8. Beaker glass 9. Bunsen burner VII. Flow Chart A. Analysis In this experiment we got sample number two which has form colourless crystal through random selection. First of all we are dividing the sample into three with ratio First, we are entering some of the sample into reaction tube. Then, we adding 6 drops of NaOH to the tube, the sample turn its form from colourless crystals to colourless solution.
After that, we are put the red litmus paper above the tube and enter the half part of the litmus into the tube. After a while the red lit- mus paper changes its colour from red to blue. Preparation of Anion Test In this experiment we analysing the contents of anion in the sample number two. First we adding saturated Na2CO3 into the sample, the sample turn its form from colourless crystal to colour solution.
Then, we heating the solution with steam bath water for about 10 minutes until white sediment formed. Next, the heating result is filtered. We obtain colour- less solution as the filtrate which will be used for anion test. Then, we are dividing the filt- rate into 3 for testing anion contents. First, we adding 2 drops of concentrate H2SO4 into the test tube which contains filtrate from prepa- ration solution. Then, we are adding saturated FeSO4 little by little through the tube wall until the brown ring is formed.
Explanation A. Here we using original sample because during the course of analysis most of the group reagents are added in the form of ammonium compound, thus by the time group V is reached, a considerable amount of ammonium ions will be built up in the test solution. The first thing that we have do is entering some of the sample into reaction tube. After a while the red litmus paper changes its colour from red to blue because the reaction produce ammonia NH3 gases which is base that can be identified from its smells and changing of litmus paper from re to blue.
Extracting anions through boiling with sodium carbonate solution has purpose to remove all heavy metals from the sample, because the heavy metal ions are precipitated out in the form of carbonates, while the anions remain in solution accompanied by sodium ions. We obtain colour-less solution as the filtrate which will be used for anion test. Then, we are dividing the filt-rate into 3 for testing anion contents.
First, we adding 2 drops of concentrate H2SO4 into the test tube which contains filtrate from prepa-ration solution. Then, we are adding saturated FeSO 4 little by little through the tube wall until the brown ring is formed. In this experiment exothermic reaction are occur because existence of H 2SO4 and it makes the tube feels hot because the heat moves from system to surrounding.
From this experi- ment, we know that in the sample number two contain of NO3- anion. Conclusion Qualitative analysis deals with the anions and cations which contain in a sample.
To analyse cations and anions have different way for each ion. To identify group I-IV cation can be done by precipitation. For group I, HCl is used as precipitator.
To provide an overview of a general scheme for separating and identifying tencations. The main tool of analytical analysis is chemical reaction as a source of information about chemical composition of substances using for qualitative and quantitative analysis. And also tell me th important properties of each anion and cation. What to record Sample Test performed Result of test What to do 1. Objective: Determine the identity of anions in a mixture. Worksheet for naming ions. Activity in classes is calculated as follows Econometrica, Vol.
AP Chemistry Lab 13 Page 1 of 8. To understand the rationale and the procedure behind the separation for various Cations and Anions. To perform Qualitative Analysis of two unknown solutions that contain various ions Cations and Anions and positively identify these ions using established schemes. To understand the rationale and the procedure behind the separation for various cations and anions. Analysis , Action , Qualitative , 13 qualitative analysis of cations and , Qualitative analysis of cations and.
A scheme of cation analysis is presented where phosphate and organic acids do not interfere with the course of analysis. The method is standardised on 2—3 mg level, and the procedure is rapid. Group separations are neat and in no case the precipitate is gelatinous. Some confirmatory tests of the elements have been modified. Einzelne Nachweisreaktionen wurden modifiziert.
The unknowns will be sodium salts of the following anions: carbonate, nitrate, nitrite, phosphate, sulfate and sulfite. HCV genotype determination Together with prior treatment experience and the presence of cirrhosis, the HCV genotype, including genotype 1 subtype 1a or 1b , is still useful to tailor the treatment regimen and its duration. Cation exchange resin; Anion exchange resin.
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Cations are identified based on their reactions with 2 reagents: aqueous sodium hydroxide and aqueous ammonia. The colour of the precipitates ppt formed and their solubility in excess of the reagent serves as a useful guide for the identification of cations in aqueous solutions. Observations: Identity of Cation Reaction with aqueous sodium Reaction with aqueous ammonia precipitate hydroxide.
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