Questions about physiological acids and alkaline salts .

Physiological acidic salts are applied in alkaline soils, and physiological alkaline salts are applied in acidic soils: plant roots are selective in the absorption of cations and anions in the same salt. When plants are cultured in a solution containing ammonium sulfate, the absorption of ammonium ions by plants is much greater than that of sulfate ions.

Since the root cells must have the same charge to exchange with the same while absorbing the environment. So the increase in the environment, the decrease in pH. Plant physiologists refer to this class of salts that acidify the soil as physiological acidic salts.

Physiological alkaline salts: When plants are cultured in a solution containing sodium nitrate, the absorption of nitrate ions by plants is greater than the absorption of sodium ions. Since the root cells must have the same charge to exchange with NO3- while absorbing the environment, the concentration in the environmental solution increases, and sodium bicarbonate is formed, and the pH of the solution rises, and it is alkaline.

Plant physiologists refer to this type of salt that alkalizes the soil as physiological alkaline salts. In agricultural production, it is important not to use a physiological acidic salt or physiological alkaline salt alone for a long time to prevent soil acidification or alkalinization.

Plant physiologists refer to this class of salts that acidify the soil as physiological acidic salts. So apply salts.

Physiological acidic salt refers to the absorption of cations by the root system after use, which is only a type of salt with increased soil acidity, and physiological alkaline salt is just the opposite! Acidic salts are suitable for use in alkaline soils, and in order to keep the soil pH close to 7, alkaline salts are used in acidic soils!

As for the elements, plants generally absorb more nitrogen, phosphorus and potassium, so you can determine what elements you need according to the amount of demand!

Plants that grow in acidic soil, use acidic salts to acidify the soil, so use acidic salts!

The acidity and alkalinity of a salt solution is the pH of the solution. The acid solution is acidic, the alkaline solution is alkaline, and the salt solution may not be neutral. In fact, some salts are acidic, some are alkaline, and some are neutral.

Strong acids: HCl, H2SO4, HNO3.

Weak acid: Common acids are weak acids except for the above three strong acids, such as H2CO3, CH3COOH, and HCl.

Strong bases: NaOH, Ca(OH)2, KOH, BA(OH)2.

Weak alkali: Common alkalis are weak alkalis except for the above four strong alkalis, such as Al(OH)3, Fe(OH)3, NH3·H2O.

Strength scale. In Arrhenius' acid-base theory, the strength of acidity and alkalinity can be quantitatively compared by the concentration of hydrogen ions and hydroxide ions in an aqueous solution (the concentration here is the activity to be precise, but the concentration of hydrogen ions in a dilute solution is close to the activity, and the activity can be replaced by a concentration that is easy to obtain data).

The concentration of hydrogen ions is expressed as c(h+), and the concentration of hydroxide is expressed as c(oh-), the greater the concentration of hydrogen ions, the stronger the acidity, and the greater the concentration of hydroxide ions, the stronger the alkalinity. At the same temperature, c(h+) c(oh-) in the aqueous solution is a fixed value, which shows that the more acidic the solution is, the weaker the alkalinity, and the more alkaline the solution, the weaker the acidity.

The acidity, neutrality or alkalinity of a solution is determined by the relative magnitude of c(h+) and c(oh-). At any temperature, the solution is acidic at C(H+)>C(Oh-), neutral at C(H+)=C(OH-), and C(H+).It is alkaline at

Acids and bases and salts are defined as:

1. Acid: The compound that generates the cation of Xiangli during ionization is all hydrogen ions (H+) is called acid, or the substance that is soluble in water and can release protons to form H3O+ (hydronium ion) is also an acid.

2. Alkali: In the theory of acid-base ionization, alkali refers to the anion ionized in an aqueous solution.

All are compounds of oh-;In acid-base proton theory, a base refers to a compound that is capable of accepting protons;In the theory of acid-base electrons.

, base refers to electron donor.

Theory of soft and hard acids and bases.

On the basis of the work of his predecessors, Ralph Pearson proposed the theory of soft and hard acid-base (HSAB) in 1963: the central atom with small size, high positive charge number and low polarizability is called hard acid, and the central atom with large volume, low positive charge number and high polarizability is called soft acid. will be electronegative.

High, low polarizability and difficult to be oxidized are called hard alkali, and vice versa is soft alkaliOther acids and bases are junctional acids and bases. The scope of application cannot include the entire Lewis acid base. System.

The solution is acidic or alkaline, depending on whether there is H+ or OH- in it, like soda ash Na2CO3, which is actually a salt, and it is called alkali because:

Na2CO3==2Na2++CO32- then CO32-+H2O==HCO3-+OH-

After sodium carbonate is dissolved in water, sodium ions and carbonate ions will be ionized, and then carbonate ions and water will react to form bicarbonate ions and hydroxide ions, because of this hydroxide, the solution is alkaline!

Judging by the composition of salt:

1) Hydrolysis of strong acid and weak alkali salt, and the solution is acidic.

2) Hydrolysis of strong alkali and weak acid salt, and the solution is alkaline.

3) Strong alkali and strong acid are not hydrolyzed, and the solution is neutral.

If pH=7, the salt solution is medium, pH》7 The salt solution is acidic, and the pH"7 salt solution is alkaline, and the smaller the pH value, the stronger the alkalinity, and the greater the pH value, the stronger the acidity.

In fact, acidity basically refers to the concentration of H ions in the solution, such as H2CO3, a molecule can ionize two H ions, but because the solubility of H2CO3 is not high, and it is easy to decompose, the ionization ability is poor, that is, the ability to ionize H+ ions is poor, so it is a weak acid. But HCl hydrochloric acid has a strong ionization capacity and hence is a strong acid.

Alkalinity is the concentration of OH- ions in the solution, Ca(OH)2 is insoluble in water, and the ability to ionize OH- ions is poor, so it is a weak base, strong bases such as KOH, NaOH is the opposite.

Salt water is neither acidic nor alkaline and is neutral.

Summary. The main ingredient in concentrated brine is sodium chloride, and sodium chloride is a strong acid and alkali salt, so it is neutral.

Is concentrated brine neutral, alkaline or acidic?

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The main ingredient in concentrated brine is sodium chloride, and sodium chloride is a strong acid and alkali salt, so it is neutral.

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1. It is not classified as acidic and alkaline, and edible salt is a neutral food.

2. The ingredient of edible salt is sodium chloride, and sodium chloride is a strong acid and alkali salt, but when the salt is dissolved in water, it is neutral. Because the anion and cation are not hydrolyzed. And the acidity and alkalinity of food is not judged by their altered taste.

The alkaline foods we encounter in life are mainly vegetables, fruits, nuts and soy products.

3. The acidity and alkalinity of food is divided according to the acidity and alkalinity of the solution after the ash is completely burned in water, acidic food refers to food with acidic solution after food ash is dissolved in water, and alkaline food refers to food food with alkaline solution after food ash is dissolved in water.