-
Anonymous users2024-02-07Acidification with hydrochloric acid (no precipitation means no silver ions, no gas release means no sulfite and carbonate), and then add BaCl2 solution, if there is precipitation, it proves that there is sulfate.
-
Anonymous users2024-02-06Strong acidification, add BACL2 solution dropwise, there is a white precipitate to form a stable existence, and there are sulfate ions.
-
Anonymous users2024-02-05Detailed analysis: The SO42-test is with Ba2+, but many interfering factors need to be excluded:
First of all. CO32-interference: BaCO3 is also a white precipitate, but it is soluble in strong acids, so it needs to be acidified with strong acids;
So, what strong acids are used for acidification?
If Hno3 is acidified, the interfering factor is SO32- (which is the doubt you mentioned), because SO32- can be oxidized by Hno3 to SO42-;
Then we use HCl acidification, but to prevent AG+ interference (add dilute hydrochloric acid without precipitation to eliminate interference);
Conclusion: Dilute hydrochloric acid was added first, and there was no precipitation. With the addition of BACL2, if there is a white precipitate, SO42- is detected.
Add dilute hydrochloric acid first, no precipitation; With the addition of BA(NO3)2, if there is a white precipitate, SO42- is detected.
They believe that the addition of dilute hydrochloric acid has removed the possible SO32-, and then the addition of BA(NO3)2 is fine.
But I think it's better to use BaCl2 because the solubility of SO2 is very high, SO2
h+no3-
Ba2+ can produce BaSO4 precipitates.
-
Anonymous users2024-02-04<> sulfate combines with metal barium ions to produce barium sulfate white precipitate, but there are many insoluble barium salts that are also white, but they are mostly soluble in acids, while barium sulfate is insoluble in acids.
Therefore, when testing sulfate ions, hydrochloric acid is usually used to acidify the experimental environment to eliminate carbonate interference, and then soluble barium salts, such as barium chloride, are added to determine whether the liquid contains sulfate ions. At the same time, it should be noted that hydrochloric acid must be added first, and then barium chloride must be added, otherwise it is easy to be disturbed by silver ions, resulting in white precipitate and affecting the inspection.
Therefore, it should be acidified first, and then tested.
1.Hydrochloric acid was added, and then the cavity precipitate was filtered out;
2.Add barium chloride and observe whether there is a white precipitate;
Ionic structure] sulfate is a tetrahedral structure formed by the connection of sulfur atoms and four oxygen atoms through covalent bonds, the sulfur atoms form bonds in sp3 hybrid orbitals, the sulfur atoms are located in the center of the tetrahedron, and the four oxygen atoms are located at its four vertices, and the bond angle of a set of S Os bonds is 109°28', the bond length of the s o bond is.
Because sulfate gets two electrons to form a stable structure, it is negatively charged, and it is easy to combine with metal ions or ammonium to produce ionic bonds and stabilize.
The structure of sulfate ions is variously stated. According to P503-505, Volume II of Inorganic Chemistry (Fourth Edition) published by Higher Education Press, "SO ions have a regular tetrahedral structure, in which the S O bond length is 149pm, which has a large degree of double bond properties. 4 oxygen atoms with.
Sulfate decomposes into sulfur dioxide and oxygen when exposed to high temperatures. Therefore, the total sulfur content of coal must be measured before combustion to reduce the emission of harmful gases.
Generally, sulfates are easily soluble in water. Silver sulfate is slightly soluble, alkaline earth metals (except BE, MG) and lead are slightly soluble in sulfate. The crystals precipitated from the solution of soluble sulfate often contain crystalline water, such as CuSO4·5H2O, FeSO4·7H2O, etc.
With the exception of alkali metals and alkaline earth metals, other sulfates have varying degrees of hydrolysis.
-
Anonymous users2024-02-03Gravimetric method: the combination of sulfate and metal barium ions will produce a white precipitate of barium sulfate, and barium sulfate is insoluble in acid. To test sulfate ions, hydrochloric acid is used to acidify the experimental environment to exclude the interference of carbonate, and then soluble barium salts, such as barium chloride, are added.
The weight of the precipitate is cooled, and then the content of sulfate ions can be calculated.
The main methods for detecting sulfate content include gravimetric method, titration method, spectrophotometry, ion chromatography (IC method), turbidity meter method, atomic absorption method (AAS), ICP-AES method, etc. Among them, gravimetric method, IC method and turbidity meter method are the three recommended methods for detecting sulfate content in oilfield water. Titration and spectrophotometry are widely used in oilfields; Spectroscopy is a new type of detection method.
-
Anonymous users2024-02-02It can be tested with barium chloride solution, dilute nitric acid, or dilute hydrochloric acid.
Take a small amount of the solution to be tested in the test tube, add dilute hydrochloric acid or dilute nitric acid, and then add chlorine with barium solution to generate a white precipitate that will not dissolve, indicating that the solution contains sulfate ions.
The ionic equation is: ba + so baso.
When testing sulfate ions, Tong Zheng Xingran often uses hydrochloric acid to acidify the experimental environment to eliminate the interference of carbonate, and then adds soluble barium salt.
-
Anonymous users2024-02-01When testing sulfate ions, in order to exclude the interference of other ions (such as carbonate ions, sulfite ions, silver ions, etc.), excessive hydrochloric acid acidification should be added first.
CO3 2- +2H+ = CO2 +H2OSO3 2- +2H+ = SO2 +H2OAG+ +3Cl- = AGCL3 plus barium chloride, if a white precipitate is produced, it can indicate that the presence of sulfate ions BA2+ +SO2- = BASO4 in the original solution can only be acidified with hydrochloric acid, not nitric acid, should be whether it is dilute nitric acid or concentrated nitric acid has oxidation, it can oxidize sulfite ions (SO3 2-) to sulfate ions (SO4 2-).
-
Anonymous users2024-01-31Hydrochloric acid is added, no bubbles are produced, and BA ions are added to produce precipitation.
-
Anonymous users2024-01-30Add dilute hydrochloric acid first, if there are no bubbles, add barium chloride to see if there is a precipitation.
This is the traditional way.
-
Anonymous users2024-01-29Add nitric acid and then add barium nitrate.
Copper sulfate itself is white, and it turns blue when it encounters water, which is why you can use dry copper sulfate to check whether the product has water.
It is a strong acid and weak alkali salt, due to the fact that the hydrolyzed solution is weakly acidic. >>>More
No, the conservation of mass is only equal to the total mass before the reaction and the total mass after the reaction, and does not mean that the mass of the solute before and after the reaction is equal, because the valency of the elements is different, so the mass of the solute before and after the reaction is not necessarily equal.
Hydrogen cannot displace copper in copper sulfate, although hydrogen is ranked before copper in the potentiometric sequence, but this is because the chemical behavior of hydrogen ions is similar to that of metal cations when they participate in the displacement reaction in water or acid solution, and it is not that hydrogen is similar to metal elements, and the basis of the potential sequence The standard electrode potential is only applicable to reactions in solution. The hydrogen in the sequence table of metal activity described in the middle school should be regarded as the criterion for the reaction between metal and acid, that is, the relative oxidation capacity of hydrogen ions and other metal cations, rather than the comparison of the size of the reduction capacity of the element, and the hydrogen element should not be taken into account.
I feel that because a small amount of sodium bisulfite is added to the barium hydroxide solution, it means that BA(OH)2 is excessive, and the HSO3 roots should be used up, so there should be no SO3 roots left, and the equation should be HSO3-+(BA2+)+OH-)==BASO3 (precipitation) + H2O. If barium hydroxide is added to the sodium bisulfite solution in reverse, it is the formula in the title above. >>>More