Qualitative and Quantitative AnalysishardNUMERICAL

The confirmatory test for the phosphate ion () involves boiling it with concentrated and adding ammoQualitative and Quantitative Analysis Chemistry Question

Question

The confirmatory test for the phosphate ion ($PO_4^{3-}$) involves boiling it with concentrated $HNO_3$ and adding ammonium molybdate to yield a canary yellow precipitate. How many atoms of Molybdenum (Mo) are present in one stoichiometric unit of this yellow precipitate?

Answer: 12

💡 Solution & Explanation

The canary yellow precipitate formed in the phosphate test is ammonium phosphomolybdate. Its exact chemical formula is $(NH_4)_3PO_4 \cdot 12MoO_3$ (or $(NH_4)_3[PMo_{12}O_{40}]$). Based on this stoichiometric formula, there are precisely 12 Molybdenum atoms in one unit.

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