Can NH4Cl be used instead of NH3 to ppt phosphorus from a fertilizer via gravimetric methods?
NH4cl is an alkaline medium but NH3 is more alkaline
so replacement can be possibly serve correct
the reaction to phosphorus is unknown to be right now
To determine whether NH4Cl can be used instead of NH3 to precipitate phosphorus from a fertilizer using gravimetric methods, we need to consider the chemical reactions involved.
In gravimetric methods, we often utilize precipitation reactions to isolate specific elements or compounds from a mixture. The choice of precipitating agent depends on the solubility characteristics of the desired compound. In this case, we want to precipitate phosphorus (in the form of phosphate ions, PO43-) from a fertilizer.
Ammonium hydroxide (NH3) is commonly used for this purpose because it forms insoluble phosphates such as ammonium phosphate (NH4)3PO4, which can be filtered and weighed to determine the amount of phosphorus present. The balanced equation for this reaction is:
3NH4OH + H3PO4 → (NH4)3PO4 + 3H2O
On the other hand, ammonium chloride (NH4Cl) does not precipitate phosphates in the same manner. When NH4Cl reacts with H3PO4, it forms soluble ammonium phosphate salt, which does not allow for a gravimetric analysis. The balanced equation for this reaction is:
NH4Cl + H3PO4 → NH4H2PO4 + HCl
Therefore, NH4Cl would not be suitable as a precipitating agent for phosphorus in the context of gravimetric analysis. NH3 (ammonium hydroxide) would be the preferred choice due to its ability to ppt phosphorus as insoluble phosphates.