How do you tell the difference between an acid and a base? Methods for identifying acids and bases a

Definition of acid-base salt: Acid: The cation produced during dissociation is a compound that is all hydrogen ions, called acid-base

The anions produced during dissociation are all compounds of hydroxide ions, called alkalis Salt: A compound of acid ions and metal ions, called salts Example: Acid:

H2SO4 (sulfuric acid), HCl (hydrochloric acid), HNO3 (nitric acid) Bases: NaOH (sodium hydroxide), KOH (potassium hydroxide), NH4OH (ammonia) Salts: Na2CO3 (sodium carbonate), CuSO4 (copper sulfate) What is Dissociation?

The so-called dissociation refers to the process by which a compound or molecule releases ions in the solvent phase For example: H2SO4 (sulfuric acid), after dissociation, H+ and SO4(2-) H2SO4====2H+ +SO4(2-) HCl==== Cl- +H+ Acid-base salt generality: Acid's universality:

Corrosive, the solution is acidic, can react with active metals, alkalis, some salts and metal oxides Alkali generality: corrosive, the solution is alkaline, can react with some metals, acids, some salts and non-metal oxides Salt universality: Some salts are weakly corrosive, the pH of the solution is judged according to the nature of the salt, can react with certain acids, alkalis, salts It can also react with some other compounds Acid-base salt reading:

Acid: The reading of oxygenated acid is to remove hydrogen and oxygen, what is left to be called acid Example: H2SO4, after removing hydrogen and oxygen, sulfur is left, so it is called sulfuric acid The reading of oxygen-containing acid is hydrogen acid Example:

HCL, there is chlorine left after hydrogen, so hydrochloric acid can be called hydrochlorate alkali: the reading of alkali is hydroxide for example: Naoh, remove hydroxide and sodium, so it is called sodium hydroxide salt:

It is generally called an acid, but there are some special readings Acid salt: called a certain acid hydrogen (acid salt is a salt with hydrogen ions) It can also be called an acid acid.

Sour; It can react with alkali to form the corresponding sulfate and water; It can react with pre-hydrogen metal under certain conditions to generate corresponding sulfate and hydrogen; Hydrolysis of proteins, disaccharides and polysaccharides can be catalyzed under heating conditions. Alkali usually refers to a bitter substance whose solution can discolor a specific indicator (such as turning litmus blue, turning phenolphthalein red, etc.), with a pH greater than 7. The ions ionized in the aqueous solution are all hydroxide ions, which react with acids to form salts and water.

Typical alkalis such as amines (including ammonia, chemical formula: NH3·H2O), caustic soda (sodium hydroxide, chemical formula: NaOH), hydrated lime [calcium hydroxide, chemical formula:

ca(OH)2], etc. A broader concept of a base refers to a substance that donates electrons, or a substance that accepts protons.

For high school content.

Let's start with the self-ionization of water.

h2o==h+ +oh-

When substances are added, this balance of water is affected.

This increases H+ or OH-.

For example, it's Na2CO3 as you said

Once added, NA+ has no effect on this balance.

After the addition of carbonate ions, some of them will combine with H+ to form bicarbonate.

This is the nature of weak acids).

As a result, there is less H+ in this balance.

Correspondingly, oh- is more.

It's alkaline.

When NaCO3 is dissolved in water, it will decompose into Na ions and CO3 ions, and CO3 ions will combine with H in water molecules to form carbonic acid, so there are more OH ions, so it is alkaline.

Add colorless phenolphthalein. If there is no change, it is acid; If it turns red, it is alkali.

Or add purple litmus. If it turns red, it is acid; If the edge is blue, it is alkali.

The method of judging acidity and alkalinity is as follows:

1. It is acid that can provide H ions, and it is a base on the contrary;

2. It is an acid that has only H ions in the cation in the solution;

3. It is an acid that can provide electrons, and the opposite is a base;

4. There are two commonly used reagents for the identification of acidity and alkalinity, phenolphthalein and litmus, litmus reagent changes color when exposed to acid, turns blue when exposed to alkali, phenolphthalein does not change when exposed to acid, and turns red when exposed to alkali. You can also use pH test strips to compare with standard color charts.

5. It is sour that has a sour taste.

The above methods can determine the acidity and alkalinity of substances, and of course experiments are the foundation of all principles.

Acidity and alkalinity are the characteristics of substances in the acid-base reaction, generally speaking, acidic substances can make purple litmus solution red, alkaline substances can make it blue, and later with the development of acid-base theory, people give a more accurate and perfect definition, and gradually touch the essence of acid-alkaline causes.

There are three scales of acidity and alkalinity: pH and POH of an aqueous solution, PKA of an acid and PKB of an alkali, and chemical hardness of an acid or base. Acidity and alkalinity are generally tested with pH test paper, litmus test solution, and phenolphthalein test solution.

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In fact, there are many ways to identify acids and bases, and here are a few common methods.

Method 1: pH test strips. When it is greater than 7, it will be bluish and alkaline; When it is less than 7, it will be reddish and acidic;

Method 2: phenolphthalein solution. The phenolphthalein solution turns red when exposed to alkali and does not change color when exposed to acid;

Method 3: Litmus solution. The litmus solution turns purple when exposed to alkali and turns red when exposed to acid;

These three methods of identifying acids and bases are the most common and I hope they will help you.

1. Acid: A compound that is composed of all hydrogen ions (H+) generated during ionization is called an acid, or a substance that can release protons to form H3O+ (hydronium ions) when dissolved in water is also an acid. 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.

2. Alkali: The anions ionized in the aqueous solution are all oh-, and the substance is a base. Such as lithium hydroxide, sodium hydroxide, rubidium hydroxide, cesium hydroxide, francium hydroxide, etc.

Tonghong chiorness 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.

In chemistry, the strength of acids and bases can be measured by the pH value. The pH sum is an indicator of the acidity or alkalinity of a solution, and can range from 0 to 14.

A pH below 7 indicates an acidic solution, and the lower the pH, the more acidic it is.

A pH of 7 indicates a neutral solution, such as purified water. Summoned.

A pH greater than 7 indicates an alkaline solution, and the higher the pH, the more alkaline it is.

Specifically, a solution with a pH of less than 3 is considered a strong acid, while a solution with a pH greater than 11 is considered to be a strong base. This is a general guiding rule, but it is important to note that the definitions of strong acids and strong bases may differ in different chemical and environmental contexts.