Solubilition Test

Water Solubility
Add approximately 6 drops of water to the test tube containing your unknown. Shake the tube and/or stir with a glass stirring rod. A soluble unknown will form a homogeneous solution with water, while an insoluble liquid will remain as a separate phase. A liquid which is soluble in water may be either a low molecular weight polar compound of up to 5 carbon atoms or less. You may add additional water, up to 1 mL, if your compound does not completely dissolve with the smaller amount.

Check the pH of the water to determine if your unknown is partially or completely soluble in water and whether your compound has changed the pH of the water.

• pH paper tus red: water soluble acidic compound
• pH paper tus blue: water soluble basic compound
• pH paper does not change color: water soluble neutral

.]

2) 5% NaOH Solubility
Add approximately 1 mL of 5% NaOH in small portions of about 6 drops each to the test tube containing your unknown. Shake test tube vigorously after the addition of each portion of solvent. Solubility will be indicated by the formation of a homogeneous solution, a color change, or the evolution of gas or heat. If soluble, then your unknown is behaving as an organic acid. The most common organic acids are carboxylic acids and phenols. Carboxylic acids are usually considered stronger acids than phenols, but both of these acids will react with NaOH (a strong base).Scheme 2).

3) 5% NaHCO₃ Solubility
Add approximately 1 mL of 5% NaHCO₃ in small portions of about 6 drops each to the test tube containing your unknown. Shake test tube vigorously after the addition of each portion of solvent. Solubility will be indicated by the formation of a homogeneous solution, a color change, or the evolution of gas or heat. If soluble, then it is a strong organic acid. If not, then it is a weak organic acid, if it dissolves in NaOH. The most common weak organic acid are phenols. Typically, only a carboxylic acid will react with NaHCO₃..

4) 5% HCl Solubility
Add approximately 1 mL of 5% HCl; in small portions of about 6 drops each to the test tube containing your unknown. Shake test tube vigorously after the addition of each portion of solvent. Solubility will be indicated by the formation of a homogeneous solution, a color change, or the evolution of gas or heat. If your compound is HCl-soluble, then it is an organic base. Amines are the most common organic base.

If insoluble in all solutions, then your unknown is not an acidic or basic organic compound.

Identification of elements in organic compounds (qualitative analysis of organic matter by alkaline melting to detect nitrogen, sulfur and halogens)

Most organic compounds are insoluble in water. So they can not be detected by dissolving in water and testing in aqueous solutions. An organic compound, even if, apart from carbon and hydrogen, it contains elements such as halogen, sulfur, nitrogen, etc., its elements will not be detectable with these common tests. To identify these elements in organic compounds, they must first be introduced into mineral compounds Ionizing was then identified. This conversion may take place in different ways, but the best way to melt compounds with sodium metal. In this method, N is converted into sodium cyanide NaCN, sulfur to sodium sulfide Na2S, and X (halogen) to sodium-halide (NaX), which is easily identifiable

Physical Properties:

The formation of PbS in the melting of alkali, which indicates the presence of sulfur

White chloride formation associated with silver chloride

Formation of Silver Yellow Bromide

Formation of Yellow Sediment Iodine

Practical section

When working with sodium, you should take all the safety precautions, and all the tools, such as a knife and a test tube, should be completely dry. Because the sodium reaction is explosive with water.

Mix 0.01 grams of the unavailable organic material and 0.005 grams of sugar or sucrose. Lacarez provides the conditions where the reduction of the elements to ion under these conditions is facilitated. In a completely dry (non-pixel and small) test tube, we make a small clean piece of sodium, approximately 4 mm in size.

(We remove sodium with a clean and dry knuckle) and we take the pipe with a clamp and warm the bottom of the tube with a short flame so that sodium is melted inside the tube and its vapors rise up to a height of about 2 cm, then the tube Remove the flame and add some of the unobtrusive material to the tube directly onto the bottom of the tube and onto the white smoke of sodium. When the material is poured into the test tube, a small explosion may occur, so this test must be carried out under the hood and under the supervision of the laboratory coach.

And then gradually heat the tube until it is red. (When heating, the pipe span should not be taken to ourselves or another person.) Similarly, add the remainder of the material and continue until it is completely blushed. Then, We will remove it from the flame to cool some. We add about 2 cc ethanol to neutralize it if sodium is present. Then bring the tube into a small human body containing 20 ml of distilled water to break it (with the help of a stirrer it can be broken). Heat the mixture inside the man to the boil and then smooth it. The solution should be clear and alkaline. If it is dark, the decomposition is likely to be incomplete and alkaline melting should be repeated.

We use the following filter solution for the following test experiments:

Identification of halogens

Silver nitrate experiment

If in the organic matter structure, nitrogen or sulfur is present, with the addition of silver nitrate to the acidic solution prepared from alkali melting, in addition to the Ag2S and AgCN silver halides, they interfere with the detection of halogens; therefore, before precipitation of AgX, the sulfur and nitrogen from the environment Extract this by adding it to the concentrated nitric acid and boil the solution to reduce its volume by evaporation, then cool and dilute with equal volume of distilled water. Then do the following experiments, if you do not have sulfur and nitrogen, you do not need to do this

A) If there is a type of halogen in the organic body, pour about 2 ml of the submerged solution of alkali melts into a test tube and acidify it with dilute nitric acid, add some silver nitrate solution, The type will be halogen, remove the supeatant from the slurry and add to the deposition of dilute ammonia solution. If the sediment is white and well diluted in ammonia, it is a sign of chlorine, and if the yellow is light and hardly soluble in ammonia (low Soluble), if it is yellow and is almost insoluble in ammonia, it is indicative of the presence of iodine in an organic body

B) If there is a mixture of several halogens:

Identify iodine

Pour 2 ml of the substrate from alkali melting into a test tube and acidify with some pure acetic acid (glacial), then add about 1 ml of carbon tetrachloride (CCL4) and drop the sodium nitrite solution dropwise Add vigorous flickering to the test tube. The purple or purple color formed in the organic layer indicates iodine is present.

After detecting iodine, use the solution of this test tube to detect bromine. Then add some sodium nitrite solution and heat it a little. Shake vigorously and wait until the two layers are separated, flush the outer layer in another cleaning tube, and discard the carbon tetrachloride violet layer. Add 1 ml of carbon tetrachloride to the overlying layer in the test tube and add a drop of 20% sodium nitrite solution while stirring up the tube. If the substrate is still poured again, the sodium nitrite solution is more poured and after Shaking and then separating the two layers, transfer the overlay to another test tube and spread the underlay layer

On the overlay layer, repeat this procedure so that no other color layer is created, then iodine is no longer in your solution. Do this on the test solution. (Note that if the purple color does not appear at the start of the experiment, it indicates the absence of iodine in the solution, and therefore there is no need to extract iodine and from the very beginning I can act to detect it.

identify of Brome

Heat the acid solution under the hood so that NO fumes do not come out, then cool. The solution is strongly acidified with glacial acetic acid and add a small amount of PbO2 lead dioxide. One

Pour a piece of the filtered fluorescein-smeared paper over the opening of the test tube around the mouth (yellow-luminescent fluoresce-based paper). The lead dioxide in the acetic acid solution produces lead acetate that oxidizes HBr and HI, but Under virtually the above conditions, HCl does not work

(1) Eocene (red) and (2) Fluorosine (yellow)

Because there is no iodine in the test tube, if the fluorescein test paper appears in pink, it is indicative of the presence of organic matter (although iodine also has such an answer, so iodine should first be completely removed from the environment and then tested I used Burm) to detect chlorine from the contents of this tubeIf the fluorescein test paper is not pink in the above test, it is because of the fact that it does not participate in the object. In this case, rinse the test tube with a little distilled water and make the solution clean and apply to the diluted solution of nitric acid and Add silver nitrate. The formation of colloidal white sediment is a sign of chlorine. But if the fluorescein test is pink in the test, continue the heat treatment so that the other paper does not make the fluorescein in pink (if necessary, again a little Add PbO and CH3COOH) Of course, this test can be applied to the initial solution obtained from the alkali nebulization I do that in that case, I'll go out and out of the operating environment, in this case, cut off the heat. After cooling the contents of the solution, rinse it with a little distilled water and add to the solution under a thin solution of dilute nitric acid and silver nitrate. The formation of white sediment indicates the presence of chlorine in an organic body. Here, the use of ammonia can not be used to dissolve this white sediment. And if you add a super-ammonia colloidal solution, the amount of white sediment will be higher. Why? (Remember: if iodine and bromine are not completely removed before, the small amount will also produce a nearly white deposit, which can

be confused with the white sediment of silver chloride)

Method for detecting halogens using chlorine water

If you have a mixture of halogens, work with chlorine water to detect each of them as follows:

Add 1 to 2 ml of the subfiltration solution obtained from alkaline melting with dilute acid chloride and add 1 ml of carbon tetrachloride and then add a drop of dilute chlorine water (by acidifying the NaCl solution with 0.2% Dilute HCl in chlorine solution) Shake this solution vigorously. If iodine exists, the carbon tetrachloride phase (the sublime phase) becomes purple. If chlorine chloride continues to increase, the purple color will first become more intense and then decrease. And eventually disappears (iodine oxidation of the colorless matter)
If there is a bromine in this experiment, the underlying layer appears in brown or red color, which will not disappear as chlorine increases. The above can not detect chlorine in an organic body

Chromatography...