Phosphates can be estimated quantitatively by precipitating them as

Options

A. `Ca_(3)(PO_(4))_(2)`
B. `AlPO_(4)`
C. `Mg_(3)(PO_(4))_(2)`
D. `MgNH_(4)PO_(4)`

Answer

4

Explanation

Phosphates precipate magnesium ammonium phosphate when added to an ammoniacal solution of magnesium chloride .If this precipitate is washed, filtered and ignited it forms magnesium diphoshate .This can weighted and thus phosphates can be estimated qantitatively.
`2Mg^(2+)(NH_(4)^(+))PO_(4)^(3)(s)rarr(Mg^(2+))_(2)P_(2)O_(7)^(4-)(s)+2NH_(3)(g)+H_(2)O(l)`