How will the reaction of $\ce{H2SO4}$ with ($\ce{NH4)2HPO4}$ [diammonium phosphate, commonly used DAP fertiliser in agriculture] proceed? Will phosphoric acid be produced, or a complex phosphate-sulphate salt would be the result?
$\begingroup$
$\endgroup$
2
-
$\begingroup$ Convenient reference for text/formula formatting: Notation basics / Formatting of math/chem expressions / upright vs italic // For more: Math SE MathJax tutorial. // Not to be applied in CH SE titles. $\endgroup$– PoutnikNov 18, 2022 at 22:06
-
$\begingroup$ Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. $\endgroup$– Kanghun KimNov 19, 2022 at 12:50
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
2
Depending on the molar ratio,
$$\ce{HPO4^2- ->[H+]H2PO4- ->[H+]H3PO4}.$$
Also remember there are no $\ce{H2SO4}$ nor $\ce{(NH4)2HPO4}$ in water solution, but $\ce{,}$ $\ce{HSO4-(aq)}$, $\ce{SO4^2-(aq)}$ , $\ce{NH4+(aq)}$ , $\ce{HPO4^2-(aq)}$, $\ce{H2PO4^-(aq)}$ and $\ce{H3PO4(aq)}$, depending on the ratio and $\mathrm{pH}$.
For direct reaction without water, then
$$\ce{2 H2SO4 + (NH4)2HPO4 -> 2 NH4HSO4 + H3PO4},$$
with some $\ce{(NH4)2SO4}$ too.
-
$\begingroup$ Thank you, that’s very helpful :). From your explanation, I conclude that if the objective is to get P04 3- (soluble form of phosphate ion in acidic PH for the crop) from DAP, then a higher concentration of H2S04 should be used than an equal moles of both, and the reaction should be carried out in water. $\endgroup$ Nov 18, 2022 at 22:26
-
$\begingroup$ PO4^3- is present only at very alkalic solutions. (pK_a3= 12.37) $\endgroup$– PoutnikNov 19, 2022 at 0:43