Answer: Answer: Ammonia water is not pure, but a mixture. It is an aqueous solution obtained by dissolving ammonia gas in water. Ammonia water consists of water molecules, ammonia molecules, monohydrate ammonia molecules, ammonium ions, hydroxyl ions, hydrogen ions, etc; The solute is ammonia monohydrate, which is pure. Ammonia water, also known as Ammonia water, is an aqueous solution of ammonia, colorless, transparent and has a pungent smell. Industrial ammonia water is an aqueous solution containing 25%~28% ammonia. Only a small part of ammonia molecules in ammonia water react with water to form monohydrate ammonia, which is a weak base only existing in ammonia water. Physicochemical properties of ammonia water: 1. Volatile ammonia water is easy to volatilize ammonia gas, and the volatilization rate increases with the increase of temperature and storage time, and the volatilization amount increases with the increase of concentration. 2. Corrosive ammonia water has a certain corrosive effect, and carbonated ammonia water is more corrosive. The corrosion to copper is relatively strong, steel is relatively poor, and cement is not corrosive. It is also corrosive to wood. 3. There is some chemical balance in weakly alkaline ammonia water, so only a small part of ammonia molecules react with water to form ammonium ions and hydroxyl ions OH -, so it is weakly alkaline. In addition, the weak alkalinity of ammonia can make the colorless phenolphthalein test solution red, purple litmus test solution blue, and wet red litmus test paper blue. This method is often used in the laboratory to test the existence of NH3. It can also react with acid to form ammonium salt. When concentrated ammonia meets volatile acids (such as concentrated hydrochloric acid and concentrated nitric acid), it will produce white smoke. If it meets nonvolatile acids (such as sulfuric acid and phosphoric acid), it will not have this phenomenon. 4. Precipitative ammonia water is a good precipitator. It can react with a variety of metal ions to generate insoluble weak base or amphoteric hydroxide. 5. Complexity reacts with Ag+, Cu2+, Cr3+, Zn2+, etc. 6. Instability It is easy to decompose into NH3 and water when heated by light. The laboratory ammonia should be sealed in a brown or dark reagent bottle and placed in a cold dark place. 7. Reductive ammonia has weak reducibility, and can be used in SNCR or SCR processes, or oxidized by strong oxidants. 8. Combustion and explosion Contact with the following substances can cause combustion and explosion: trimethylamine, amino compounds, alcohols, aldehydes, organic anhydride, alkenyl oxide, etc. Main use of ammonia water: used as agricultural fertilizer. In the chemical industry, it is used to manufacture various ammonium salts, organic synthetic aminating agent, and catalyst for producing thermosetting phenolic resin. In the textile industry, it is used in wool spinning, silk, printing and dyeing industries to wash oil stains on wool, woolen cloth and grey cloth, assist in dyeing and adjust the pH value. In addition, it is used for alkalization of pharmaceuticals, tanning, hot water bottle bile (prepared with silver plating solution), rubber and grease.
