Is it true that you should use vinegar to neutralize lye?

If you've seen the movie Fight Club, there's a scene where lye is poured on Edward Norton's character's hand and Brad Pitt's character tells him that using water would make the chemical reaction worse, and should use vinegar instead. Does anyone know if this is true? Some people say it's the exact opposite. Which one wil produce an exothermic reaction with the lye and which one would neutralize it?Is it true that you should use vinegar to neutralize lye?
Lye is sodium hydroxide (NaOH).





Brad Pitt is sort of right in this one. If it's a solid (and there is no moisture on your hand) it's not a problem. However, when you add water (even the little bit of water from perspiration), it will dissolve the NaOH and dissociate it into Na+ ions and OH- ions. The former are harmless. The latter will cause caustic burns. Adding water will make more OH- ions.





Rinsing it with vinegar (acetic acid, CH3COO-H or H-Ac for short) will neutralise it, though this is also exothermic. The reaction is:





Na-OH + H-Ac --%26gt; H2O + Na-Ac





(actually, it's Na+ + OH- + H+ + Ac- --%26gt;H2O + Na+ + Ac- )





This will happen very fast, and produce a lot of heat, which will cause burns. So the best way is to rinse as much of it off quickly with water and then neutralise the tiny bit that's left with vinegar.





The important point here, though, is that by asking this question, you're breaking the FIRST RULE OF FIGHT CLUB!Is it true that you should use vinegar to neutralize lye?
No, you do not want to pour an acid (even though acetic acid is considered weak) on top of a strong alkali like lye (sodium hydroxide).





First, you want to use copious amounts of water to wash as much of the lye away as possible, and then clean up with a DILUTE solution of acetic acid.





NEVER EVER APPLY AN ACID DIRECTLY TO A BASE in full strength. Not unless you want an explosion, or serious accident.