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Writing Net Ionic Equations
Posted: Sun Oct 07, 2012 9:18 pm
by superrad
"Consider the reaction when aqueous solutions of ammonium iodide and potassium phosphate are combined." Then I need to write the net ionic equation.
When I try to write down the equation I get it as:
NH4I+KH2PO4=(NH4)3PO4+KI
Which is apparently an impossible reaction. What am I doing wrong?
Re: Writing Net Ionic Equations
Posted: Sun Oct 07, 2012 11:06 pm
by GrahamKemp
First, determine which potassium phosphate you're dealing with. Monopotassium dihydrogen phosphate, Dipotassium hydrogen phosphate, or Tripostassium phosphate?
Second, just swap the potassium atoms with an equal number of ammonium groups.
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Ammonium iodide + Monopotassium dihydrogen phosphate = Ammonium dihydrogen phosphate + Potassium iodide.
NH4I + KH2PO4 = (NH4)H2PO4 + KI
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Ammonium iodide + Dipotassium hydrogen phosphate = Diammonium hydrogen phosphate + Potassium iodide.
2 NH4I + K2HPO4 = (NH4)2HPO4 + 2 KI
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Ammonium iodide + Tripotassium phosphate = Triammonium phosphate + Potassium iodide.
3 NH4I + K3PO4 = (NH4)3PO4 +3 KI