[AlwaysQuestioning]

Hi guys. Just curious as to what makes strong alkalis in particular (e.g NaOH) so caustic/ corrosive.
Does it have to do with the hydroxide ion that forms when it dissolves in any form of moisture ? (Sweat) And anyone can help with my iron oxides/rusting questions too (Also in this section of the forum).


Thanks so much. I tried to find the answer for this but to no avail. Thanks in advance.

[Dan]

Corrosion is caused by chemical reactions that beak down a material - hydroxide is a pretty reactive base and nucleophile, so it will corrode materials composed of acids and/or electrophiles.

The reason it burns your skin is hydrolytic degradation of lipids (a.k.a. saponification).

[antimatter101]

Fats are basically glycerol esters. (1,2,3-propanetriol) Where long chain carboxylic acids or other compounds are attached by ester bonds to the glycerol oxygens. Esters are electrophilies, and do undergo nucleophilic attack to form the carboxylate anion and alcohol. So caustic substances hydrolyse the fats and lipids in your cells and to immense damage to the structure. Acids are similar.