Hydroxiden

Hydroxiden, in English hydroxides, are chemical species that contain the hydroxide ion, OH−. They commonly form salts when combined with metal cations and most hydroxides act as bases in chemical reactions. In aqueous solutions they are sources of hydroxide ions that raise pH and neutralize acids.

The hydroxide ion consists of a negatively charged oxygen bound to hydrogen. When dissolved in water, hydroxide ions participate in acid–base chemistry, typically accepting protons to form water. Solubility and basicity vary with the accompanying cation. Alkali metal hydroxides (LiOH, NaOH, KOH, RbOH, CsOH) are highly soluble in water and are strong bases. Alkaline earth hydroxides (e.g., Ca(OH)2, Ba(OH)2) are less soluble and still behave as bases, though to a lesser extent in solution.

Preparation and occurrence: hydroxides can form by reacting a metal oxide with water, by precipitation from salts, or by industrial processes such as the electrolysis of brine to produce sodium hydroxide. They are also encountered as minerals in geology, and as components of many industrial formulations.

Common examples include sodium hydroxide, potassium hydroxide, and calcium hydroxide. These substances participate in neutralization reactions with acids (for example, NaOH + HCl → NaCl + H2O) and can react with carbon dioxide to form carbonates (2 NaOH + CO2 → Na2CO3 + H2O). They are widely used in manufacturing, water treatment, soap production, and chemical synthesis.

Safety: hydroxides are caustic and corrosive; handling requires appropriate protective measures.