Ito ay isang uri ng inorganic compound, na kilala rin bilang caustic soda, caustic soda, caustic soda, sodium hydroxide ay may malakas na alkaline, sobrang kinakaing unti-unti, maaaring magamit bilang acid neutralizer, na may masking agent, precipitating agent, precipitation masking agent, color agent, saponification agent, pagbabalat ahente, detergent, atbp, ang paggamit ay napakalawak.