Complementary to its reactivity toward acids, KOH attacks oxides. Thus, SiO2 is attacked by KOH to give soluble potassium silicates. KOH reacts with carbon dioxide to offer potassium bicarbonate:KCN is used like a photographic fixer within the moist plate collodion method.The KCN dissolves silver where it hasn't been made insoluble by the develo