alkalines

Alkalines, or alkalis, are bases that dissolve in water to form alkaline (basic) solutions with a pH greater than 7. In chemistry, alkalis are a subset of bases that are soluble in water; many bases, by contrast, are insoluble and not considered alkalis. When dissolved, alkalis release hydroxide ions (OH−) that raise the solution’s pH and enable neutralization of acids.

Common alkalis include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), and ammonium hydroxide (NH4OH). They may also arise from oxides that form hydroxides when hydrated, such as calcium oxide (CaO) reacting with water to give Ca(OH)2. Alkalis are used to adjust pH, neutralize acidic waste streams, and in processes such as soap making, food preparation, and paper production.

Alkalinity in water chemistry refers to the capacity of water to neutralize added acid and is primarily due to carbonate (CO3^2−), bicarbonate (HCO3−), and hydroxide (OH−) ions. While this property is related to alkalis, it is a separate measurement used in environmental science and water treatment.

Safety and handling: many alkalis are caustic and corrosive, capable of causing chemical burns on skin and eye exposure; contact should be avoided, and protective equipment used when handling concentrated solutions. Spills should be contained to prevent environmental damage.