Re: Questions about activity series
- From: terphenyl@xxxxxxxxxxx
- Date: 29 Jul 2006 17:31:11 -0700
Lloyd Parker wrote:
In article <1153940564.760487.270750@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,More information about monocalcium phosphate chemistry than you can
"TheAndroid" <a_w_abate@xxxxxxxxx> wrote:
Sorry about the previous empty post. Stupid ENTER key!!!!!
I am puzzled about something I observed the other day. I took 2g of
CaH2PO4 (0-48-0 fertilizer) and dissolved it in 100g of water. So far,
so good. I expected this to yield CA+ H3O+ and PO4-3 ions in solution.
In fact, the pH of this solution dropped from 7.1 to 2.1 once
everything dissolved, so I think I got what I had expected.
From H2PO4(-1), you'd get H+ and HPO4(2-) with it acting as an acid, and
OH(-) and H3PO4 with it acting as a base -- H2PO4(-) is amphoteric. You
wouldn't get a measurable amount of PO4(3-), as that would be a second
dissociation of the HPO4(2-) produced in the first dissociation.
My first question is this: Is it correct to expect multiple cations
from this molecule?
Once I had this, I took a 1990 penny and scratched up the surface. I
dropped the penny into the solution expecting the exposed zinc to
liberate the hydrogen. I closed up a ZipLoc bag around the liquid and
the penny to hold any freed gas. The bag while well sealed, did not
expand. Instead, I think the Ca reacted with the zinc.
My next question is: Why would this have happened? Ca is higher than
Zn in the activity series. Is it because Ca is also higher than H?
My next question is: I really want to liberate the Ca from the
solution (refine out the phosphoric acid for later use). Am I
effectively doing this with the Zn or is it simply replacing the Ca
cations?
And finally: If I bubble hydrogen through water, can I eventually
end up with a glass of hydronium (H30)?
Thanks in advance.
shake a spatula at:
www.ams.usda.gov/nop/NationalList/TAPReviews/monocal.pdf
.
- References:
- Questions about activity series
- From: TheAndroid
- Questions about activity series
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