In: Chemistry
Phosphoric acid is a triprotic acid. Calculate the [PO4^3-] if you start out with 5.00 M phosphoric acid.
Phosphoric acid is triprotic (H3PO4)
Given : [H3PO4] = 5 M
.
1. ...(1)
I | 5 | - | 0 | 0 | |
C | -x | - | +x | +x | |
E | 5-x | - | x | x |
From recation (1) we get,
but, x << 5 Therefore,
Hence,
ie.
2. ...(2)
We have, and
Therefore,
3.
we have, ,
and
Therefore,