Acid throwing and readily available in many instances. For example, often acid throwers can purchase a liter of concentrated sulfuric acid at motorbike mechanic shops for about 40 U.S. cents. Nitric acid costs around $1.50 per liter and is available for purchase at gold or jewelry shops, as polishers generally use it to purify gold and metals. Hydrochloric acid is also used for polishing jewelry, as well as for making soy sauce, cosmetics, and traditional medicine/amphetamine drugs. Due to such ease of access, many organizations call for a stricter regulation on the acid economy. Specific actions include required licenses for all acid
Lewis acid catalysis Lewis acid catalysis In Lewis acid catalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc) d-block metals. The metal atom forms an adduct with a lone-pair bearing electronegative atom in the substrate, such as oxygen (both sp or sp), nitrogen, sulfur, and halogens. The complexation has partial charge-transfer character and makes the lone-pair donor effectively more electronegative, activating the