110 million tonnes are applied each year. Precursor to nitrogenous compounds Ammonia is directly or indirectly the precursor to most nitrogen-containing compounds. Virtually all synthetic nitrogen compounds are derived from ammonia. An important derivative is nitric acid. This key material is generated via the Ostwald process by oxidation of ammonia with air over a platinum catalyst at , ≈9 atm. Nitric oxide is an intermediate in this conversion: Nitric acid is used for the production of fertilizers, explosives, and many organonitrogen compounds. Ammonia is also used to make the following compounds: Hydrazine, in the Olin Raschig process and the peroxide process Hydrogen cyanide, in the BMA process and the Andrussow process Hydroxylamine and ammonium carbonate, in the Raschig process Phenol, in the Raschig–Hooker process Urea, in the Bosch–Meiser urea process and in Wöhler synthesis Amino acids, using Strecker amino-acid synthesis Acrylonitrile, in the Sohio process Ammonia can also be used to make compounds in reactions which are not specifically named. Examples of such compounds include: ammonium perchlorate, ammonium nitrate, formamide, dinitrogen tetroxide, alprazolam, ethanolamine, ethyl carbamate, hexamethylenetetramine, and ammonium bicarbonate. Cleansing agent Household "ammonia" (more correctly called ammonium hydroxide) is a solution of in water, and is used as a general purpose cleaner for many surfaces. Because ammonia results in a relatively streak-free shine, one of its most common uses is to clean glass, porcelain, and stainless steel. It is also frequently used for cleaning ovens and for soaking items to loosen baked-on grime. Household ammonia ranges in concentration by weight from 5% to 10% ammonia. US manufacturers of cleaning products are required to provide the product's material safety data sheet which lists the concentration used. Solutions of ammonia (5–10% by weight) are used as household cleaners, particularly for glass. These solutions are irritating to the eyes and mucous membranes (respiratory and digestive tracts), and to a lesser extent the skin. Experts advise that caution be used to ensure the chemical is not mixed into any liquid containing bleach, due to the danger of forming toxic chlorine gas. Mixing with chlorine-containing products or strong oxidants, such as household bleach, can generate toxic chloramine fumes. Experts also warn not to use ammonia-based cleaners (such as glass or window cleaners) on car touchscreens, due to the risk of damage to the screen's anti-glare and anti-fingerprint coatings. Fermentation Solutions of ammonia ranging from 16% to 25% are used in the fermentation industry as