How to detect CO32 and eliminate SO32 interference

can turn these weak acids into gas.

co32-+2h+=co2+h2o

so32-+2h+=so2+h2o

Summary. Heating HCO3 - a solution that can generate heat that makes the clarified lime water cloudy gas, whether hydrogen ions are produced, make the clarified lime water cloudy gas, carbon dioxide and sulfur dioxide gas for commercial bodies, magenta does not fade CO32-

The presence of SO32- interferes with the identification of CO32- How can it be prevented?

Heating HCO3 - a solution that can generate heat to make the clarified lime water cloudy gas, whether slippery to produce hydrogen ions, make the clarified lime water cloudy gas guess round, carbon dioxide and sulfur dioxide gas commodity body, magenta does not believe in trillion-pure fading CO32-

**: Expansion: Add barium chloride solution to the solution to produce a white precipitate, take the white precipitate and add dilute hydrochloric acid, and the colorless gas that produces mountain void can not fade the bromine water, that is, it contains carbonate ions.

The colorless gas produced can not fade the bromine water, and the purpose of guessing the ear color is to eliminate the interference of sulfur dioxide produced by sulfite ions when it meets acid.

If the test solution is acidic, it is impossible for any anion to exist.

The main acids are: silver ions, barium ions, hydroxide ions, etc., which may form precipitate and water ions. Alkaline ones include: copper ions, calcium ions, etc., which may generate precipitate and water ions.

Generally speaking, the sulfate is tested with a barium ion Ba2+ because BaSO4 is a white precipitate that is insoluble in water and insoluble in acid

Moreover, BaCl2 is generally used instead of BA(NO3)2, because if the solution to be tested is acidic, the NO3- produced by ionization of BA(NO3)2 has strong oxidizing properties (equivalent to nitric acid), and may react with the solution (for example, the original solution contains SO3 2- and will be oxidized).

The reason why it is said that AG+, CO3 2-, SO3 2- will interfere with the test is because:

AG+ reacts with Cl- to form AGCL, and CO3 2-, SO3 2- and BA2+ react with BA2+ to form BAC3 and BaSO3, all of which are white precipitates.

Among them, AGCL is insoluble in acids, while the other two are soluble in acids.

Let's look at the reaction between hydrochloric acid and three ions

CO32- reacts with hydrochloric acid to produce CO2 and H2O

Ag+, which reacts with Cl- in hydrochloric acid, is to form AgCl precipitate.

SO32- reacts with hydrochloric acid to form SO2 body and H2O (nitric acid oxidizes SO32- so it is not used).

Sulfate, on the other hand, does not react with hydrochloric acid.

Therefore, after adding excessive hydrochloric acid to the solution, if there is no precipitation, and then adding bacl2, there is still a white precipitate, which can indicate the existence of sulfate. (If there is a precipitate after adding excessive hydrochloric acid, it means that the original solution contains Ag+, at this time, the agCl precipitate is filtered out before adding BaCl2, in order to facilitate the distinction of Baso4.)

I think that it is heated first, and only HCO3 - can be heated to produce a gas that makes the clarified lime water turbid, and then hydrogenation ions. Carbon dioxide and sulfur dioxide can be, and then the gas is passed through the product solution, and the magenta does not fade is CO32-.

、Everything for your liking