Ions that can t coexist in solution? Grade 9 Chemistry .

H2O gases and precipitated ions cannot meet each other, and generally cannot coexist in large quantities.

For example, H+ and OH- cannot coexist, it should be H+ +OH-=H2OH+ CO32- and 2H+ +CO32- =H2O+CO2 cannot coexist

Generate precipitation: for example, oh- and fe3+ mg2+ cu2+ cannot coexist.

H+ and OH- (acids and bases), which react to form H2O; hydrogen ions and carbonate ions, which react to produce carbon dioxide; It can react to generate precipitated ions (see solubility table), alkali and ammonium ions, and produce ammonia gas That's all you come into contact with.

That's a lot! Like what; 1 BE+ cannot coexist with SO42- 2 CA2- cannot coexist with CO3 2- 3 AG+ cannot coexist with Cl- 4 MG2+ cannot coexist with OH-. Anyway, it's a bit much, I can't finish it for a while, give me a little rating, thank you!!

The inability to coexist means that a reaction occurs, forming a precipitate or gas. None of the following two ions can coexist in the solution. Cu2+ and -OH, Ca2+ and CO32-, Ag+ and Cl-, Ba2+ and SO42-, Fe3+ and -OH, Cu2+ and -OH

As long as you can produce water, gas, or sediment, you can't coexist, just remember which substances are insoluble in water, and it's very simple.

Those that meet the conditions for metathesis reaction, that is, they can generate precipitates, gases, and weak electrolytes. Redox reactions can occur in general, strong oxidizing ions and strong reducing ions. Also, pay attention to the colored ions.

When certain ions in the solution can react with each other to form insoluble substances, they cannot coexist in large quantities.

Such as SO42- and Ba2+, PB2+, AG+;

OH with Cu2+, Fe3+, Mg3+, Al3+, Zn2+;

AG+ and Cl, Br, I, Co, So, S2;

Mg2+, Ca2+, Ba2+, and CO3 2-, SO3 2-, etc., cannot coexist in large quantities. When ions can combine to form hard-to-ionize substances, these ions cannot coexist in large quantities. For example, H+ and, OH, clo, CH3COO, HPO4 2-, H2PO4-OH and HCO3-, HS, HSO3-, H2PO4-, Hpo4 2-, H+, etc. cannot coexist in large quantities.

When ions can combine to form volatile substances, these ions cannot coexist in large quantities. Such as H and CO32-, SO3-, HCO3-, HSO3-, S2, HS; OH cannot coexist in large quantities with NH, etc.

When redox reactions can occur between ions, these ions cannot coexist in large quantities. Generally speaking, oxidizing ions (such as MNO, Clo, Fe3+, Hno3, etc.) and reducing ions (such as S2, I, Br, SO, Cl, Fe2+, etc.) cannot coexist in large quantities.

Hydrolyzable cations and hydrolyzable anions cannot coexist in large quantities in aqueous solution. Examples: Al3 and HCO3-, Al3 and S2, etc.

In acidic or alkaline media, it cannot coexist in large quantities due to redox reactions. For example, NO3- and I- can coexist in neutral or alkaline solutions, but cannot coexist in the presence of a large amount of H+; SO32- and S2- can also coexist under alkaline conditions, but cannot exist under acidic conditions due to the occurrence of the 2S2- SO32- 6H+ 3S 3H2O reaction

Can generate precipitates, microsolutes, gases, two or more of water can not coexist, other basically can, 4, redox, precipitation, gas, 1, the conditions for the coexistence of ions:

Interaction between two ionsIf a substance such as water, gas, or precipitate is formed, the two ions cannot coexist in the same solution.

Common non-coexisting ions in junior high school chemistry are as follows:

1）h++oh-→h2o ；（2）h++co32-→co2↑；（3）nh4++oh-→nh3↑；

4）ba2++so42-→baso4 ↓（5）ag++cl-→agcl ↓；

6）ca2++co32-→.1. First of all, if the ions in the solution want to coexist, they must not react with each other.

The conditions under which the metathesis reaction takes place, that is, the exchange of anions and cations between two compounds to form two new compounds - the reaction product must be formed by one of the precipitates, gases, and water. It can be seen that if the ions contained in the solution can form one of the above three substances, they cannot coexist.

I don't know if you get it. Let me give you a few examples.

If in the solution of sodium carbonate [Na2CO3]: it is obvious that Na+ and CO3- are one of the precipitated gases that cannot be formed. If.

1. In a strong acidic solution, it is not possible to shout that there are weak acid ions in the rotation: such as carbonate (CO3 2), bicarbonate (HCO3), sulfur ion (S2), thiohydrogen ion (HS), sulfite ion (SO3 2), silicate ion (SiO3 2), metaaluminate ion (ALO2), fluoride ion (F), etc., nor can there be a large amount of hydroxide (OH).

In a strong alkaline solution, there should be no weak alkali metal ions in large quantities. Such as: magnesium ion (Mg2+), ferrous ion (Fe2+), iron ion (Fe3+), aluminum ion (.

0, the common ones in junior high school are H+ and OH-Ca2+ and CO32- Ba2+ and SO4, 2-AG+ and Cl- Cu2+ and OH-Fe3+ and OH-Fe2+ and OH-Ba2+ and CO32-To judge whether it can be reflected, it depends on whether these two ions can react Can not coexist If you can't react, you can coexist If you can't react, you should remember the following sentences to determine whether the ions in the junior high school stage coexist potassium, sodium, ammonium and nitrate are soluble in water, (potassium salt, sodium salt, ammonium salt, nitrate can be soluble in water, and these four ions can coexist with other ions in water and dissolve in water. 0,

1. Hydroxide ions cannot coexist with colorless ions such as hydrogen ions, ammonium ions, acid acids of weak acids, and silver ions in solution. It cannot coexist with colored ions such as iron ions (yellow), ferrous ions (light green), and copper ions (blue).

2. Hydrogen ions cannot coexist with hydroxide ions, weak acid acids, weak acid acid acids, etc.

3. If the precipitate can be generated, it cannot coexist, such as barium ions and sulfate ions and carbonate ions in colorless solutions; Silver ions cannot coexist with chloride ions, bromine ions, iodide ions, etc.; Aluminum, metaaluminate and hydrogen cannot coexist in solution.

4. If the redox reaction can occur, it cannot coexist in large quantities, such as ferrous ions, nitrate ions, and hydrogen ions cannot coexist in the solution.

Colored ions in secondary school: dichromate ion (orange), permanganate ion (purple), iron ion (yellow), ferrous ion (light green), copper ion (blue).

There are two categories, one is to meet the conditions of metathesis reaction (can combine with each other to form water, gas, or precipitation), and the other is to have redox reactions between each other (mainly oxidizing ions and reducing ions).

For example: the first category: hydrogen ions, hydroxide ions, weak acid ions can not coexist in large quantities Barium ions, sulfate ions, and carbonate ions cannot coexist in large quantities;

Silver ions and chloride ions cannot coexist in large quantities.

Hydroxide ions cannot coexist in large quantities with iron, magnesium, copper, zinc and other ions.

The second category: hydrogen ions, nitrate ions and ferrous ions can not coexist in large quantities at the same time When solving the problem, you should also pay attention to the requirements of the solution color in the question, the solution containing some ions is colored, and the problem will sometimes tell the acidity and alkalinity of the solution, the acidic solution contains a large number of hydrogen ions, and the alkaline solution has a large number of hydroxide ions.

The basis for judging that ions cannot coexist in large quantities.

In a strong acidic solution, there can be a large number of weak acid ions: such as carbonate (CO32), bicarbonate (HCO3), sulfur ion (S2), hydride ion (HS), sulfite ion (SO32), silicate ion (SiO32), metaaluminate ion (ALO2), fluoride ion (F), stearate ion, etc., nor can there be a large number of hydroxide (OH).

In a strong alkaline solution, there should be no weak alkali metal ions in large quantities. For example, magnesium ions (Mg2+), ferrous ions (Fe2+), iron ions (Fe3+), aluminum ions (Al3+), copper ions (Cu2+) and ammonium ions (NH4+), etc., can not exist in large quantities of hydrogen ions (H+) and acid root ions

HCO3, HSO3, HS, H2PO4, etc.

Ions that can undergo redox reactions cannot coexist: e.g., Fe3+, Cu2+ and I, H+, I, Fe2+ and NO3, S2, Fe2+ and Clo, H+, I and SO32 or S2, etc.

Those that can form complex ions cannot coexist: such as: Fe3+ and SCN, AG+ and SO32, Fe3+ and C6H5O, etc.

(1) Formation of insoluble substances or microsolubles: Ba2+ and CO32, AG+ and Br, Ca2+ and SO42 cannot coexist in large quantities.

2) Formation of gases or volatile substances: such as NH4 and OH, H and CO32, HCO3, S2, HS, HSO3, SO32, etc. can not coexist in large quantities.

3) Generate substances that are difficult to ionize: such as H and AC, CO32, S2-, SO32, etc., to form weak acids; OH and NH4, Cu2+, Fe3, etc. form weak bases; H with OH to form water, and these ions cannot coexist in large quantities.

4) Redox reaction: oxidizing ions (such as Fe3+, NO3, CLO, Mno4, etc.) and reducing ions (such as S2, I, Fe2+

SO32, etc.) cannot coexist in large quantities.

Note that Fe2+ and Fe3+ can coexist.

5) Formation of complexes: For example, Fe3+ reacts with SCN- to form complexes and cannot coexist in large quantities.

Ions that do not produce precipitates, gases, colloids, or complexes coexist in large quantities in solution.

What doesn't react can coexist, and what can react can't. Therefore, if there is gas, precipitation, weak electrolyte formation, or redox reaction, it can react.

If precipitation, gas, weak electrolyte is not generated, and redox reaction does not occur, just pay attention to the examination conditions.

Conditions for ion coexistence: acid-base neutralization does not occur; No gas and precipitation are generated; No redox reaction occurs (i.e., valency rises and falls), remember which are oxidizing ions and reducing ions hypochlorite, can not coexist with positive divalent iron ions, pay attention to the acidity and alkalinity of the solution, hydrogen ions and nitrate coexist with strong oxidation, can not coexist with positive divalent iron ions, chloride ions.

Hypochlorite ions'It can coexist in an alkaline environment, but not in an acidic environment. Keep in mind common insoluble substances, microlytic substances, etc.