Why is it said that acids are acidic substances, and acidic substances are not necessarily acids

Generally speaking, acidic substances refer to substances with only hydrogen ions in cations during ionization, note that it is "only", and acid salts such as sodium bicarbonate, cations have sodium ions and hydrogen ions when ionized, and of course they are no longer in the category of acids.

The above ones are incomplete, and those greater than 7 are alkaline.

Less than 7 is acidic.

It is only true in water at 20 degrees Celsius, like in water, pH 6 is neutral.

Generally speaking, the concentration of H ions in water is greater than the concentration of OH ions, because acids can ionize a large number of H ions in water, so acids are acidic substances, but there are some strong acids and weak alkali salts, which will be hydrolyzed in water, so that the concentration of H ions in water is higher than the concentration of oh ions, and they become acidic, so they are also acidic substances. Like NH4Cl, etc., are acidic, so they are also acidic.

I don't know how much you've learned now, I'm sorry, I don't know how much you know.

This question is more technical.

Acids are all substances that can ionize hydrogen ions.

Acid, on the other hand, refers to a substance that ionizes hydrogen ions by itself.

Lewis, for example, is not an acid, but he can ionize hydrogen ions in solution.

Generally this substance is a weak acid!

An acidic substance is not necessarily an acid: for example, copper ions in copper sulfate water are decomposed to make it an acid, while copper sulfate is not an acid.

Acids are acidic ::liuxingrain is right.

Acids and alkaline substances are judged based on the value of pH, and those greater than 7 are alkaline.

Less than 7 is acidic.

And when you say acidity, it's taste.

Taste is not the only judge, as some substances are acidic but not sour

Here's an example. Sodium bisulfate is not an acid, but it can also produce hydrogen ions with electricity.

In other words, acidic salts are acidic substances, not acids.

It's not that complicated, it's just that the substance name confuses you, as if sweet is sugar, and sugar is not necessarily sweet (starch is also a sugar substance, just like a pear is a fruit, but a fruit is not a pear, right?).

The reference here is something corrosive.

Acids are compounds that are ionized with all cations made of hydrogen ions (H+), or substances that dissolve in water and release protons to form H3O+ (hydronium ions). The nature of the acid is corrosive. Most of these substances are soluble in water, and a few are such as:

Silicic acid, insoluble in water. An aqueous solution of an acid generally conducts electricity, and its conductive properties are related to its degree of ionization in water.

The narrow definition of acid in chemistry is: the cations ionized in an aqueous solution are all hydrogen ion compounds. Proposed by Arrhenius, this theory is known as Arrhenius' acid-base theory.

Most of these substances are soluble in water, and a small part, such as silicic acid, is insoluble in water. An aqueous solution of an acid generally conducts electricity, and its conductive properties are related to its degree of ionization in water.

Related information

Acids are used in a wide range of industries, and many industries and laboratories use acids, and the commonly used ones are sulfuric acid, hydrochloric acid, and nitric acid. Many chemical dust removal reactions are carried out in aqueous pH where the pH is important. If carbon dioxide is injected into a solution containing Ca2+, whether calcium carbonate precipitate can be obtained depends on the pH value of the solution.

Some reactions must be carried out at a constant pH value, for which a solution of a weak acid (base) and its salts is often used as a buffer solution.

Normal human blood pH which contains HCO and HCO (HPO and HPO) A slight change in health will affect health. Therefore, it is mostly expressed in the form of chemical equilibrium rather than complete reaction, and the weak brigade school Zen acid refers to the acid that is not completely dissociated. It is not obvious to use the acidity coefficient as a difference between strong and weak acids (because the numerical difference is difficult to understand and not obvious), so it is more reasonable to use the equation to distinguish between the two.

It's not a misunderstanding of many people, in fact, things that taste sour are not all classified as acidic foods: for example, fruits such as oranges and apples taste sour because they do contain fruit acids, but they will form alkaline substances that are absorbed after being oxidized by the digestive system, so they belong to alkaline foods instead; However, for example, meat, egg yolk and other foods do not taste sour at all, but because they contain more sulfur, chlorine and other elements, they are acidic foods formed after digestion and oxidation in the body. Another example:

Almost all fruits and vegetables are alkaline foods, with the common exception of strawberries, which are acidic.

The division between acidic and alkaline foods is not based on taste, but on the ingredients they contain.

The acidity and alkalinity of food refers to whether the inorganic salts in the food are acidic or alkaline. The acidity and alkalinity of food depends on the type and amount of minerals contained in the food: potassium, sodium, calcium, magnesium, and iron enter the human body to show an alkaline reaction; Phosphorus, chlorine, and sulfur are acidic when they enter the human body.

From a nutritional point of view, acidic foods and alkaline foods should be consumed, and a reasonable combination and alkaline ones are the guarantee of good health. Understanding this truth, we know that either the taste is sour or acidic food, and strawberries and citrus are just alkaline foods. Alkaline foods mainly include:

Fruits and vegetables, nuts, seaweed, sprouted cereals and legumes. Acidic foods include: meat, desserts, cheeses, etc.

Actually, this is not accurate. The acidity and alkalinity of food is not based on taste.

In food science, there are acidic foods and alkaline foods. However, its division is not differentiated according to the sourness of the taste.

In the chemical analysis of food, if the ash left after the combustion of food contains more phosphorus, sulfur and chlorine, it can form an acidic solution after being dissolved in waterIf the ash contains more potassium, sodium, calcium, and magnesium, it can form an alkaline solution after being dissolved in water, which is the origin of the acidity and alkalinity of food.

Generally speaking, high-protein foods such as meat and eggs and high-starch foods such as rice and noodles contain more sulfur, phosphorus and other elements, which will form acidic substances after metabolismVegetables, fruits, milk and other foods contain more minerals such as potassium and calcium, and the alkalinity of metabolites is stronger. Therefore, most fruits and vegetables are alkaline foods, while most meats are acidic foods.

And many sour foods, such as many fruits such as oranges, lemons, plums, etc., which are like to eat, are instead alkaline foods.

Strawberries, citrus, etc., are also alkaline foods, not acidic foods.

Acidity and sour taste are two different concepts. The concept of acidity is scientifically a chemical concept, and sourness is the smell and taste that people feel with their tongue or nose in their daily life (of course, there are exceptions, some people, obviously sour, he says it is tasteless).Substances that are acidic are not necessarily acids, such as ammonium chloride.

Why acids have similar chemical properties

Different acid solutions contain the same hydrogen ions, so acids have similar chemical properties.

The definition of acid is that the cations ionized are all hydrogen ions in order to be called acids, and since they are all hydrogen ions, there is a certain similarity in properties.

Because the essence here is hydrogen ions, of course, the presence of other anions will affect the chemical properties of the acid, for example, hydrochloric acid has the reducing property because of chloride ions, nitric acid has strong oxidation because of nitrate, concentrated sulfuric acid has strong oxidation because of the concentration relationship, to see clearly the factors that determine the chemical properties.

For example, hydrochloric acid contains hydrogen ions and chloride ions, and sulfuric acid solutions contain hydrogen ions and sulfate ions, and their solutions all contain the same hydrogen ions, so they can all react with acid-base indicators, active metals, basic oxides, bases and salts, and have similar chemical properties.

According to the degree of ionization of acid in aqueous solution, there are strong acids and weak acids, and it is generally believed that strong acids are completely ionized in aqueous solutions, such as hydrochloric acid and nitric acid; Weak acids are partially ionized in aqueous solutions, such as acetic acid, carbonic acid.

The ionization equilibrium of weak acids present in aqueous solution is as follows

Ha] [H+] A-] is the amount concentration of the substance of Ha H+ A-, respectively, which is the ionization equilibrium constant of the weak acid Ha. For example, at 298K, the ionization constant of acetic acid is hydrofluoric acid. The ionization equilibrium constant varies slightly with the concentration and temperature of the weak electrolyte.

At a certain temperature, the ionization degree of weak acid increases due to the thinning of the solution, such as the ionization degree of acetic acid, which is completely ionized when diluted indefinitely.

Acidity: refers to the ability of a substance to supply hydrogen ions to other substances in a solvent. At 25 degrees Celsius, when the concentration index value of hydrogen deficiency ion is less than 7, the solution is acidic.

In a sense, acidity is inversely proportional to oxidation.

There are many examples of this, such as strong acids, weak alkali salts and some acid salts are acidic, here are just a few examples:

1. Strong acid and weak alkali salts:Copper sulphate (chemical formula: cuso), ferric chloride (chemical formula:

mgbr), copper chloride (chemical formula: CuCl)....

2. Acid salt:Sodium bisulfate (chemical formula: Nahso), potassium bisulfate (chemical formula:

nahso₃）…

Vinegar tastes sour, but the essence is alkaline.

Well, because the definition of acid and base in chemistry before high school is actually confused.

If you really want to encounter the test, you can just take a strong acid salt, such as sodium bisulfate (non-strong acid salt, remember that there is only one common --- dihydrogen phosphate that will be acidic. ）

Acid: Chemically refers to the substance that the cation is completely hydrogen ion when ionized in the solution, and the nature of the acid is the property of hydrogen ion, which has universality: it can change the color of indicators such as purple litmus test solution, react with alkali and metal oxides to form salts, etc.

In a narrow sense, it can also be divided into inorganic acids and organic acids. The acid-base proton theory holds that acid is a substance that can release protons, which is collectively called acid.

Compounds that produce all positive ions during ionization are hydrogen ions are called acids.

Junior Chemistry Experiment - Chemical Properties of Acids.