Is dry ammonia alkaline and why is ammonia alkaline

From the point of view of protic acid, dry ammonia is not alkaline.

According to Arrhenius' theory of acid-base ionization, the freely moving anions produced during ionization are all oh- compounds, which are bases. According to this theory, ammonia is not alkaline and is not alkaline, ammonia is dissolved in water to produce ammonia monohydrate, and ammonia monohydrate is partially ionized.

NH3·H2O = NH4+ +OH- (reversible).

Therefore, ammonia monohydrate is a weak alkali and is alkaline.

However, the ionization theory is an early acid-base theory, and then the acid-base theory has been developed by leaps and bounds, and the proton theory and the electron pair theory have been put forward successively.

According to the bronsted-lowry acid-base proton theory, anything that can provide protons is an acid, and anything that can accept protons is a base. According to this theory, the ammonia molecule has a pair of lone electron pairs, which can coordinate to the H+ (proton) empty orbital, and can accept protons to form NH4+, so it is a base and is alkaline.

According to Lewis theory of acid-base electron pairs, anything that accepts electron pairs is an acid, and a base that provides an electron pair. According to this theory, the ammonia molecule can provide electron pairs, which is a base and is alkaline.

From the point of view of protic acid, dry ammonia and sulfur dioxide are not acidic or alkaline.

When ammonia is dissolved in water, ammonia molecules and water molecules are combined into ammonia monohydrate (NH3 H2O) through hydrogen bonds, and ammonia monohydrate can be ionized into ammonium ions and hydroxide ions in a small part, so ammonia is weakly alkaline and can make the phenolphthalein solution red. The reaction of ammonia in water can be expressed as:

Ammonia monohydrate is unstable and decomposes by heat to produce ammonia and water.

There are three molecules, three ions, and three equilibrium in ammonia.

Molecules: NH3, NH3, H2O, H2O;

Ions: NH4+, OH-, H+;

Three balances: NH3+H2O NH3 H2O=NH4++OH-H2O =H++OH-

Ammonia. There is some chemical equilibrium in .

Therefore, only a small fraction of ammonia molecules react with water to form ammonium ions.

and hydroxide ion oh-, so it is weakly alkaline.

In addition, the weak alkalinity of ammonia can make colorless phenolphthalein test solution.

Turning red can make the purple litmus solution blue, and can make the wet red litmus paper blue. This method is commonly used in laboratories to test for the presence of NH3. It can also react with acids to form ammonium salts. Concentrated ammonia encounters with volatile acids such as concentrated hydrochloric acid.

and concentrated nitric acid) will produce white smoke, if you encounter non-volatile acids (such as sulfuric acid, phosphoric acid), you don't know that there will be this phenomenon in the mountains.

The uses of ammonia are divided into:

1. Industrial use: wool spinning, silk, printing and dyeing and other industries are used to wash wool, woolen wool, grey fabric, dissolve and adjust pH.

and as a dyeing aid, etc. It is used as an amination agent in the organic industry and a catalyst for the production of thermosetting phenolic resins, and in the inorganic industry it is used to prepare various iron salts.

2. Laboratory use: Ammonia is an important reagent in the laboratory, mainly used as an analytical reagent, neutralizing agent and alkaloid.

Leaching agents, aluminum salt synthesis and weakly alkaline solvents. It is used for the synthesis of aluminum salt and the verification and determination of certain elements, so as to precipitate hydroxides of various elements.

3. Agricultural use: It can be used as fertilizer after dilution in agriculture, and the application principle of ammonia is "one does not leave the soil, and the other does not leave the water". To not leave the soil is to cover the soil deeply; Staying water-free means diluting with water to reduce concentration, reduce volatilization, or in combination with irrigation.

Since ammonia is less dense than water, care should be taken to avoid excessive accumulation in local areas and burn the plants when irrigating. Ammonia can be used as base fertilizer or top dressing.

The above content refers to Encyclopedia - Ammonia.

Alkali lime should be used for drying ammonia.

and other alkaline desiccant.

Ammonia is alkaline when soluble in water, so it cannot be dried with acidic desiccant, such as concentrated H SO, PO, Songchang concentrated H SO, and NH react with NH to form ammonium salt.

NH) so, P o is easy to form acid when exposed to water, so it will react with NH.

Due to calcium chloride.

Absorb ammonia, nor can it dry ammonia. Anhydrous CaCl can react with NH, CaCl +8NH = CACL ·8NH is larger.

Test method for ammonia.

Method 1: Test with moistened red litmus test paper, and the test paper turns blue to prove that there is ammonia.

Method 2: Use a glass rod dipped in concentrated hydrochloric acid.

Approaching, white smoke is produced, which proves the presence of ammonia. NH + HCl = NH Cl (White Solid) Method 3: Ammonia Detection Instrument can quantitatively measure the concentration of ammonia in the air. Years of cherry blossoms.

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Ammonia (NH3) is alkaline and it can dissociate hydrogen ions (H+) in water to form ammonium hydroxide (NH4OH), i.e., NH3 + H2O NH4OH. This chemical reaction is known as the ammonia-water reaction, in which ammonia is a weak base that is able to accept hydrogen ions from the potato bend in the water to produce ammonium hydroxide. This means that if an acid is added to ammonia, such as hydrochloric acid (HCl), the hydrogen ions in the ammonia will bind to the chloride ions in the hydrochloric acid, reducing the alkalinity of the ammonia.

Conversely, if a base is added to the ammonia, such as sodium hydroxide (NaOH), the hydroxide ion will seize the hydrogen ions in the ammonia molecule, inhibit the formation of NH4OH, increase the content of NH3, and thus enhance the alkalinity of ammonia. <>

Ammonia is a weak alkaline gas, which is judged according to the characteristics that ammonia can turn the colorless phenolphthalein test solution red and the purple litmus test solution turn blue after being dissolved in water.

The chemical formula of ammonia is NH3, the molecular weight is, under standard conditions, the density is , and the relative density air = . It can be liquefied by pressurization at room temperature (critical temperature, critical pressure megapascals, that is, atmospheric pressure), boiling point, and is also easily solidified into a snow-like solid, melting point, soluble in water, ethanol and ether.

The role of ammonia.

1. Ammonia can be used to make ammonia, nitrogen fertilizer, compound fertilizer, nitric acid, soda ash, etc.;

2. Ammonia is widely used in chemical industry, light industry, chemical fertilizer, synthetic fiber, pharmaceutical and other fields;

3. Ammonia can be used as a detergent, neutralizing agent, and alkaloid leaching agent;

4. Ammonia is also used as a biofuel to provide energy;

5. Ammonia is used as an amination agent in the organic industry and a catalyst for the production of thermosetting phenolic resins.