Sodium hydroxide (NaOH), yomwe imadziwikanso kuti lye ndi caustic soda, ndi gawo lachilengedwe. Ndi choyera choyera komanso chosalala kwambiri chachitsulo komanso mchere wa alkali wa sodium womwe umapezeka m'matumba, ma flakes, granules, komanso mayankho okonzedwa m'malo osiyanasiyana. Sodium hydroxide amapanga pafupifupi 50% (kulemera) njira yodzaza ndi madzi .; Sodium hydroxide imasungunuka m'madzi, ethanol, ndi methanol. Alkali iyi ndiyowoneka bwino ndipo imatenga chinyezi ndi mpweya woipa mlengalenga.