On Fri, 17 Sep 2004 13:12:31 -0400, someone wrote:

The acid you use for etching cement is probably HCl, which ought to react with
the
cement to produce mostly calcium cloride (a salt) and free hydrogen.
Nuetralizing the excess using backing soda, (sodium bicarbonate) should
produce sodium cloride, (table salt) more calcium cloride, and some free gasses.

The runoff will be salty water.

Wouldn't it be a better general principle to put the baking soda down
first, and let the acid wash run into it (far away from where on is
standing)? I'd generally not want to stand there and pour a base into
an acid without a protective suit, but OK maybe its so dilute that
its just a theory, but as a general principal....

-v.