|When placed in citric acid, what happens to iron?
Iron with slowly start "rusting" which is a
process by which iron oxides and hydroxides form.
It will not necessarily happen because of the
citric acid --- most acids would start the process
of rusting. The many things that take place are
very involved and somewhat complex, but the
reddish-brown product (rust) is known to be mostly
a compound called lepidocrocite with the formula
The hydrogen ions in the acid strip the electrons
off of the iron and turn into neutral hydrogen.
Meanwhile, the iron corrodes because it is
changing into ionic form (and probably
crystallizing out some kind of salt or rust).
If you put iron in citric acid (or other acids) it
will dissolve quite quickly. It may look like it
is also rusting, but that is probably from the
water that is usually also in the liquid (example:
lemon juice has both water and citric acid).
Click Here to return to the search form.