colorless gas with a pungent smell of ammonia NH3 is not only readily soluble in water with liberation of heat.Active substance interacts with H2O molecules to form weak alkali.The solution has received several names, one of them - ammonia water.The compound has surprising properties, which are in the process of formation, composition and chemical reactions.
Education ammonium ion
Formula ammonia water - NH4OH.The composition of matter is present cation NH4 +, which is formed nonmetals - nitrogen and hydrogen.N atoms in a molecule of ammonia is used for the formation of covalent polar bonds only 3 of the 5 outer electrons, and one pair remains unclaimed.In a highly polarized water molecule hydrogen protons H + are weakly bound to oxygen, one of them becomes a donor to the free electron pair of nitrogen (acceptor).
formed ammonium ion with one positive charge and a special type of a weak covalent bond - donor-acceptor.For its size, charge and some other features it resembles the potassium cation and behaves like an alkali metal.Unusual in terms of the chemical compound reacts with acids forming salts having a great practical importance.The names that reflect particular preparation and properties of the substance:
- ammonia water;
- ammonium hydroxide;
- ammonium hydroxide;
- ammonium hydroxide.
Precautions must be taken when working with ammonia and its derivatives.It is important to remember:
- Ammonia water has an unpleasant smell.The escaping gas irritates the nasal mucosal surface of the eye, causing coughing.
- When storing ammonia in a loosely closed vials, ampoules released ammonia.
- can detect without instruments, just by smell even a small amount of gas in solution and air.
- ratio between the molecules and cations in solution varies at different pH.
- at approximately 7 reduces the concentration of toxic gas NH3, an increasing number of less harmful to living organisms cations NH4 +
Getting ammonium hydroxide.Physical properties
The dissolution of ammonia in water is formed ammonia water.Formula of the substance - NH4OH, but in fact both ions are present
NH4 +, OH-, NH3 and H2O molecules.In the chemical ion exchange reaction between ammonia and water, an equilibrium condition.The process can be reflected by the circuit on which the oppositely directed arrows indicate the reversibility of the phenomena.
in the laboratory to obtain ammonia water is carried out in the experiments with nitrogen-containing compounds.When mixed with ammonia water to obtain a transparent colorless liquid.At high pressures the solubility of the gas increases.Water longer sends dissolved therein ammonia at higher temperatures.For industrial needs and agriculture on an industrial scale receive a 25 percent compound when dissolved ammonia.The second method uses the reaction of coke oven gas with water.
chemical properties of ammonium hydroxide
When contacting the two liquids - ammonia water and hydrochloric acid - are covered by clouds of white smoke.It consists of particles of the reaction product - ammonium chloride.With such a volatile substance such as hydrochloric acid, the reaction takes place in the air.
Low-alkali chemical properties of ammonium hydroxide:
- substance reversibly dissociates in water to form ammonium cation and the hydroxide ion.
- In the presence of NH4 + ion is colorless phenolphthalein turns crimson, as with lye.
- Chemical neutralization with acid results in the formation of ammonium salts and water: NH4OH + HCl = NH4Cl + H2O.
- Ammonia water enters the ion exchange reaction with the metal salts, which correspond to the weak base, thereby forming a water-insoluble hydroxide: 2NH4OH + 2NH4Cl = CuCl2 + Cu (OH) 2 (blue precipitate).
Ammonia water: application in various sectors of the economy
unusual substance widely used in households, agriculture, medicine and industry.Technical ammonium hydroxide is used in agriculture, production of soda ash, dyes and other products.The liquid nitrogen fertilizer plants contained in easily digestible form.The substance is considered to be the cheapest and most effective for the period of inclusion in the seedbed for all crops.
on the production of ammonia water consumed three times less funds than on the issue of solid granular nitrogen fertilizer.For storage and transportation of liquid applied hermetically closed tanks are of steel.Some types of paints and means for bleaching the hair are made using ammonium hydroxide.In each facility there are drugs with ammonia - a 10-percent solution of ammonia.
Ammonium Salts: properties and practical significance
Substances which are prepared by reacting aqueous ammonia with an acid, are used in economic activity.The salts are decomposed by heating, dissolved in water, are subjected to hydrolysis.They enter into chemical reactions with alkalis and other substances.The most important practical value acquired chlorides, nitrates, sulfates, phosphates and carbonates of ammonium.
It is important to observe rules and security measures, work with substances, which is composed of ammonium ion.When stored in the warehouses of industrial and agricultural enterprises, farms should not be a contact of these compounds with lime and alkalis.If leakproof packaging, then start a chemical reaction with the release of toxic gas.Anyone who has to work with water and ammonium salts thereof, must know the basics of chemistry.Subject to the requirements of safety precautions used substance does not bring harm to people and the environment.
