Can Ca ions coexist in large quantities with OH root ions

On the issue of ion coexistence in solution.

The essence of the problem of ion coexistence in solution is which ions cannot react with each other. Ions that can react cannot coexist, and ions that cannot react can coexist in large quantities.

1. When some ions in the solution can react with each other to form insoluble substances and slightly soluble substances, these ions cannot coexist in large quantities.

2. When ions can combine to form difficult ionization substances, these ions cannot coexist in large quantities.

3. When ions can combine to form volatile substances (gases), these ions cannot coexist in large quantities.

4. When redox reactions can occur between ions, they cannot coexist in large quantities, so these ions cannot coexist in large quantities. Generally speaking, oxidizing ions (such as Mno4, Clo, Fe3+, NO3, etc.) and reducing ions (such as S2, I, Br, SO32, Fe2+, etc.) cannot coexist in large quantities.

Ca2+ and OH- cannot coexist in large quantities. It is mainly the soluble strong alkali Naoh, Koh, Ba(OH)2 that reacts with the soluble calcium salts CaCl2, Ca(NO3)2.

No, calcium hydroxide is slightly soluble, and the specific needs to be calculated by KSP, but the statement that a large number of coexist is false.

Let's look at the OH root (which binds to these ions to form a precipitate): Mg2+, Modified Lead Al3+, Mn2+, Zn2+, Fe3+, Fe2+, Cu2+, Ca2+ (slightly soluble).

CO3 roots (combined with these ions to form precipitate): Ba2+, Ca2+, Mn2+, Zn2+, Fe3+, Cu2+, Ag+

SO4 (combined with these ions to form sedimentation and annihilation) roots: Ba2+, Ca2+ (microlytic hall).

Cl ions (combined with these ions to form precipitates): AG+

Of course, acids and alkalis cannot coexist for the most part. That is, h+ and oh- cannot coexist.

You have to remember that to see if two substances coexist is to see if there is precipitation, gas, water formation in these two reactions, and if at least one of the above three substances is formed, then they do not coexist.

If there are no other ions in the solution, it is not possible to select Na ions. Because Na, NH4 and Shouqing BA ions are all positive ions, there are no negative ions, and the solution is positive and negative.

This is what the question should mean, and you must choose a negative departer to hold the ball. Hydroxide, sulfate obviously can't. Chloride ions are no problem.

So choose A for this question.

FYI.

Let's start with OH roots (which bind to these ions to form precipitates): Mg2+, Al3+, Mn2+, Zn2+, Fe3+, Fe2+, Cu2+, Ca2+ (slightly soluble).

CO3 roots (combined with these ions to form precipitate): Ba2+, Ca2+, Mn2+, Zn2+, Fe3+, Cu2+, Ag+

SO4 (conjugated to these ions to form a precipitate) root: Ba2+, Ca2+ (slightly soluble) Cl ions (conjugated to these ions to form a precipitate): Ag+

Of course, acids and alkalis cannot coexist for the most part. That is, H+ and OH- cannot coexist, you have to remember that to see if two substances coexist is to see if there is precipitation, gas, water formation in these two reactions, and if at least one of the above three substances is generated, then they do not coexist.

Hydrogen ions, magnesium ions, silver ions, fluoride ions, a small amount of aluminum ions, ferric ions, divalent iron ions, copper ions, ammonium ions, 、...

There's nothing that can't, it's just a matter of quantity.

Iron ions and carbonate will be dihydrate 2Fe3+ +3CO32-+3H2O ===2Fe(OH)3 +3CO2

This is because complete dihydrolysis occurs between the two, resulting in iron hydroxide and carbon dioxide, which cannot coexist in solution.

2fe3+ +3co32- +3h2o=2fe（oh）3↓+3co2↑

Both ferric and ferric iron form precipitates with carbonate ions.

Calcium hydroxide is slightly soluble in water, and the concentration of calcium ions and root clearing ions is not high, and it cannot exist in large quantities.

It can react, because the solubility of calcium hydroxide is small (slightly soluble), when the concentration of sodium hydroxide and calcium chloride is large, there is calcium hydroxide precipitation.

ca2+ +2oh- = ca(oh)2

Yes, it is difficult for CA examples and OH ions to coexist.

In an alkaline solution, all weakly alkaline cations.

and H+ cannot coexist in large quantities. In middle school chemistry, the ones that cannot coexist in large quantities in alkaline solution are: H+, Fe2+, Fe3+, Cu2+, Ag+, Zn2+, Mg2+, Al3+, NH4+, HCO3-, HPO42-, H2PO4-, HSO3-, HS-, Hooc-

coo- etc.

You are talking about potassium ions (k+).

Hydroxide ion (oh-).

Chloride ions. cl-）

Carbonate ions can coexist in large quantities in alkaline solutions.

Whether the ions coexist can be judged by whether the ions are suppressed or whether they can react.

There are 3 types of ions that react with OH-:

Formation of insoluble substances (precipitate): OH- and Fe3+

fe2+mg2+

Cu + Ca2+ (calcium hydroxide.

Slightly soluble) ag+ (agoh is a white precipitate, easy to decompose into brown silver oxide.

and water) here corrects the strong alkali under calcium hydroxide

Formation of volatile substances (gases): NH4+

Formation of a substance that is difficult to ionize (e.g., spine water): H+

hco3-、hpo42-、h2po4-、hso3-、hs-、hooc-

Let's start with OH roots (which bind to these ions to form precipitates): Mg2+, Al3+, Mn2+, Zn2+, Fe3+, Fe2+, Cu2+, Ca2+ (slightly soluble).

CO3 roots (combined with these ions to form precipitate): Ba2+, Ca2+, Mn2+, Zn2+, Fe3+, Cu2+, Ag+

SO4 (conjugated to these ions to form a precipitate) root: Ba2+, Ca2+ (microrapid lease solubilization) Cl ions (conjugated to these ions to form a precipitate): AG+

Of course, acids and alkalis cannot coexist for the most part. That is, H+ and OH- cannot coexist, you have to remember that to see whether the two substances coexist is to see whether there is precipitation, gas, and water in the absence of liquid in these two reactions, and if at least one of the above three substances is generated, then they do not coexist.