Estimation of phosphorous:
Second method: A known mass of compound is heated with fuming `HNO_(3)` or sodium peroxide `(Na_(2)O_(2)` in Carius tube which converts phosphorous to `H_(3)PO_(4)`. Magnesia mixture `(MgCl_(2)+NH_(4)Cl)` is then added, which gives the percipate of magnesium ammonium phosphate `(MgNH_(4).PO_(4))` which on heating gives magnesium pyrophosphate `(Mg_(2)P_(2)O_(7))` , which is weighted.
Percentage of P`=("Atomic mass of P")/("Molecular mass of " Mg_(2)P_(2)O_(7)) xx ("Molecular mass of "Mg_(2)P_(2)O_(7) xx 100)/("Mass of compound")=(62)/(222) xx("Mass of " Mg_(2)P_(2)O_(7)xx 100)/("Mass of compound")`
0.12 gm of and organic compound containing phosphorus gave 0.22 gm of `Mg_(2)P_(2)O_(7)` by the usual analysis. Calculate the percentage of phosphorus in the compound.
A. 25
B. 9.25
C. 801
D. `51.20`
