Bases, Strong

Materials in this group are mostly nonflammable and non-combustible. Exceptions include mixtures that contain organic components.

Compounds in this group are chemically similar to sodium hydroxide (NaOH) or sodium oxide (Na2O). They neutralize acids exothermically to form salts plus water. When soluble in water they give solutions having a pH of 12 or higher. Mixing these materials with water can generate significant heat as the base is dissolved or diluted. Bases react with certain metals (such as aluminum and zinc) to form oxides or hydroxides of the metal and generate gaseous hydrogen. Bases may initiate polymerization reactions in polymerizable organic compounds, especially epoxides. They may generate flammable and/or toxic gases with ammonium salts, nitrides, halogenated organics, various metals, peroxides, and hydroperoxides. Materials of this group often serve as catalysts.

Corrosive to tissue.

Solutions of bases have a bitter taste and a slippery feel; they turn red litmus blue. (Note: This reactivity group does not include Metal hydrides, alkyls and aryls and silanes, which are also strong bases with additional hazards, but are covered under Reactive Group 35). They possess a pKa value greater than 12 or a pH value greater than 12.

Sodium hydroxide, potassium hydroxide, barium hydroxide, barium oxide, calcium oxide, sodium methoxide, tetramethylammonium hydroxide.