Milk of Magnesia, or MOM, is a suspension of Mg(OH)2. One method for determining the amount of Mg(OH)2 in MOM is to precipitate the Mg2+ as MgNH4PO4. Because this precipitate includes a weak acid, NH4+, and a weak base, PO43-, it is reasonable to expect its solubility to be pH dependent. Draw a single ladder diagram showing the distribution of PO43- species on the left and NH4+ species on the right. Based on your ladder diagram, determine the range of pH values for which the solubility of MgNH4PO4 is likely to be at a minimum. Be sure to explain your reasoning.
Solubility of Milk of Magnesia
About the Author
David Harvey
David T. Harvey is a Professor Emeritus of Chemistry and Biochemistry at DePauw University in Greencastle, Indiana, where he has been a dedicated faculty member since 1986. Over his nearly four-decade career, Dr…
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