Ammonium chloride, with the chemical formula NH4Cl, is a chemical compound composed of ammonium ions (NH4+) and chloride ions (Cl-). It is a white crystalline salt that is highly soluble in water and has a salty taste.

Ammonium chloride has several key properties and uses, including:

1. Flux in Soldering: Ammonium chloride is used as a flux in soldering processes. It helps remove metal oxides from the surface of metal parts, ensuring better adhesion of solder and improved soldering quality.
2. Fertilizer: It is used as a nitrogen-based fertilizer in agriculture. The ammonium ions in ammonium chloride provide essential nitrogen for plant growth.
3. Dry Cell Batteries: Ammonium chloride is used in some types of dry cell batteries as an electrolyte.
4. pH Control: It is used to control pH levels in certain industrial processes.
5. Textile Printing and Dyeing: Ammonium chloride is used in some textile printing and dyeing processes.
6. Cough Medicines: Ammonium chloride has been used in some cough medicines as an expectorant, helping to thin and loosen mucus in the respiratory tract.

Ammonium chloride is generally considered safe for its intended uses, but like any chemical compound, it should be handled with care. Ingestion of large quantities can cause health issues, and inhalation of its dust can irritate the respiratory system. Proper safety measures and handling procedures should be followed when working with ammonium chloride to prevent accidents and ensure personal and environmental safety.