Ammonium Hydroxide is a colourless solution of Ammonia in water with a pungent odour. It is usually found in concentrations of up to 30% and is used in household cleaners, photography, fertilizers, textiles, rubber, and pharmaceuticals, as well as as a refrigerant.

Ammonia water has many applications in industry as well as in laboratories:

Ammonium hydroxide solution is an essential tool in the manufacturing process of chemical fertilizers. It is used as a solution or as salt in these fertilizers.

Ammonium hydroxide is also used to produce organic and inorganic chemicals containing nitrogen. It is the base chemical in the manufacture of nitric acid.

A 1-3% solution of NH4OH is used in cleaning agents such as window-cleaning liquids. A solution of Ammonia in water (scented or plain) is also sold directly as a cleaning agent.

Ammonia can be used in the production of chloramine, which is a good disinfectant. It remains active in still water for longer durations than chlorine.

Any wood that contains tannic acid can be sealed in a container with an ammonium hydroxide solution to give a dark-stained look to the wood. Thus, the ammonium hydroxide solution is used in furniture darkening.

Basic substance

Ammonium hydroxide has a very high pH, making it an alkaline or basic substance. By definition, this means ammonium hydroxide isn't an acid, as acids have pH levels lower than 7, which is the neutral level. By comparison, one mole of this solution has a pH of 11.3. According to the Bronsted-Lowry theory of acids and bases, an acid donates protons, and a base is a proton acceptor. The proton here is a hydrogen ion, which is just a proton. A substance doesn't necessarily have to have a hydrogen or hydroxide ion to be considered either an acid or a base. As long as the condition of acting as a proton donor or acceptor is fulfilled, a substance can be classified as either an acid or a base.