How to distinguish between acid and alkali salts, and how to distinguish acid and alkali salts simpl

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In terms of composition: the substances formed by metal cations (including NH4+) and hydroxide anions are bases. Such as koh, naoh, etc.; The substance formed by metal cations (including NH4+) and acid anions is salt.

Such as K2SO4, NH4NO3, etc.; The substance formed by H and acid anions is acid. Such as HNO3 and H2SO4.

Bases--- metal cations (including NH4+) and hydroxide anions.

Acids--- hydrogen ions Acid ions.

Salts --- metal cations (including NH4+) and acid anions.

Your question is a bit big and the point is not very clear.

Judging by the question, you should be a junior high school student who has just learned chemistry.

1) From the chemical formula, it is concerned that there is an oh- in the back, an acid, and a salt, which is composed of metal cations and acid anions (there is also a type with NH4+).

But in fact, it is more complicated than this, and some are difficult for beginners to distinguish, such as NH3, H2O, HCL, HCL gas is acid after dissolving in water, H2O is neutral (because we generally say acid and alkali salt, that is, water is regarded as neutral as the standard), and NH3 itself is only a hydride, not belonging to the category of acid and alkali salt, but its aqueous solution NH3·H2O (there are also textbooks written as NH4OH) is a base.

2) From the experimental point of view, it is the problem of acidity and alkalinity of the solution, the solution with more oh- than H+ is the alkaline solution, the equal is the neutral solution, and the less is the acidic solution. This is another problem with acid-base salts.

Therefore, for beginners, sort out the textbook first, take your time, and accumulate it, with the increase of learning time, all students have no problem distinguishing between acid and alkali salts, at least I have not encountered it for so many years. Hold your horses!

Acids and alkalis can first be distinguished conceptually:

The dissociated cations are all hydrogen ion compounds, which are acids. The dissociated anions are all compounds of hydroxide ions, which belong to bases.

Compounds that are made up of metal ions or ammonium ions and acid ions are salts.

It can also be distinguished from the name, a certain acid belongs to acid; Hydroxide belongs to alkali, and hydroxide (except for oxidation) and acid generally belong to salt.

The method of distinguishing acid-base salts is as follows:

The formula for distinguishing acid-base salts: a compound with all cations H+ is an acid, a compound with an anion all oh- is a base, and a compound composed of metal ions and acid ions is a salt.

Potassium, sodium, ammonium, nitrate dissolves quickly, and sulfate removes barium lead. Chloride is insoluble in silver chloride, and nitrate solutions are transparent. None of the mantras are sinking.

Acids: Acids are also acids in compounds that are ionized with all cations made up of hydrogen ions (H+), or substances that dissolve in water and release protons to form H3O+ (hydrated hydrogen ions). Such as hydrochloric acid, sulfuric acid, carbonic acid, nitric acid, etc.

Universality of acids: acid solution can react with acid-base indicators, acid + alkaline oxide = salt + water, etc.

Alkali: The anions ionized in an aqueous solution are all oh- substances, which are bases. Such as lithium hydroxide, sodium hydroxide, rubidium hydroxide, cesium hydroxide, francium hydroxide, etc.

Universality of alkali: the alkali solution can react with the acid-base indicator, the purple litmus test solution turns blue when it encounters alkali, and the colorless phenolphthalein test solution turns red when it encounters alkali.

Salts: Compounds in which metal ions or ammonium ions (NH4+) are combined with acid ions or non-metal ions are salts. Such as sodium chloride, calcium nitrate, ferrous sulfate and ammonium acetate, calcium sulfate, copper chloride, sodium acetate, etc.

Salt generality: some salts have weak corrosiveness, the pH of the solution is judged according to the nature of the salt, can react with certain acids, alkalis, salts, and other hidden compounds.

Sour:It is composed of hydrogen ions (H+) and acid anions, such as HCl, H2SO4

Alkali:It is composed of hydroxide ions (OH-) and metal cations, such as NaOH and KOH

Salt:It is composed of metal cations or ammonium ions (NH4+) and acid anions, such as NaCl, NH4Cl

Sour:The cations produced when ionized in an aqueous solution are all compounds of hydrogen ions (H+);

Alkali:The anions ionized in the aqueous solution are all hydroxide ion (OH-) compounds;

In acid-base proton theory, a base refers to a substance that is capable of accepting protons; In acid-base electron theory, base refers to electron donor. ）

Salt:Refers to a compound consisting of metal ions or ammonium ions (NH4+) combined with acid ions or non-metal ions.

Chemical properties of acid-base salts.

Sour:

1) It can react with acid-base indicator, purple litmus test solution turns red when it is acid, and colorless phenolphthalein test solution does not change color when it meets acid;

2) It can react with multi-excitation retardation of active metals, usually to produce salts and hydrogen. Only metals that precede hydrogen in the order table of metal activity can react with dilute acids to produce hydrogen. Metals located after hydrogen cannot react with dilute acids, but can react with oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid;

3) It can react with alkaline oxides to form salts and water;

4) It can react with certain salts to form new acids and new salts;

5) It can neutralize with alkali to form salt and water.

Alkali:

1) Neutralization reaction with acid;

2) reacts with certain non-metallic oxides;

3) Turns purple litmus blue; reddens colorless phenolphthalein;

4) It can react with certain salts to form new salts and new alkalis.

Salt:

1) Displacement reaction: In the order of metal activity, only the metals in front can be replaced from their salt solution;

2) react with certain metals to generally form another salt and another metal;

3) It can react with acid to generally form another salt and another acid;

4) It can react with alkali to generally form another salt and another alkali;

5) It can react with another salt, generally to produce two other salts.

Hydrogenic acid, hydroxide at the end, alkali, metal at the beginning, acid at the end, and salt at the end. Next, the definition and differentiation of acid-base salts are shared for reference.

Definition of acid-base salts.

1.Acids: Acids are also acids in compounds that produce all cations (H+) when ionized, or substances that dissolve in water and release protons to form H3O+ (hydronium ions).

2.Alkali and Nian: In the aqueous solution, the ionization of the anions out of the tent bridge is all oh-, and the substance is a base. The alkali solution can react with the acid-base indicator, the purple litmus test solution turns blue when it encounters alkali, and the colorless phenolphthalein test solution turns red when it encounters alkali.

3.Salts: Compounds in which metal ions or ammonium ions (NH4+) are combined with acid ions or non-metal ions are salts.

Methods for distinguishing between acids and alkalis.

Most acids are soluble, and silicic acid is slightly soluble. Alkali potassium sodium barium ammonium soluble, calcium is slightly soluble and insoluble. Lead barium sulfate is immersed in water, slightly soluble calcium, silver and mercury.

The salts are dissolved with potassium, sodium ammonium, plus soluble nitrate. Carbonic acid can dissolve potassium and sodium ammonium, and the rest is submerged in the middle. Hydrochloric acid precipitates silver mercurous, as well as slightly soluble lead chloride.

Acid-base salt solubility formula.

Potassium sodium ammonium salt nitrate, easily soluble in water.

Sulfates are also soluble, but calcium, barium, and silver should be removed.

In addition to silver mercurous hydrochloride, carbonic acid and phosphate are only soluble in potassium sodium ammonium.

Bases--- metal cations (including NH4+) and hydroxide bimon anions.

Acids--- hydrogen ions Acid ions.

Salts --- metal cations (including NH4+) and acid anions.