Question

0.12g of organic compound containing phosphorus gave 0.22g of Mg₂P₂O₇ by the usual analysis. Calculate the percentage of phosphorus in the compound.

Answer 1

Here the mass of the compound taken = 0.12g

Mass of Mg₂P₂O₇ formed = 0.22g of atoms of P

Now 1 mole of Mg₂P₂O₇ = (2x24+2x31+1687)

i.e; 222g of Mg₂P₂O₇ contain phosphorus = 62g.

∴ 0.22g of Mg₂P₂O₇ will contain phosphorus.

But this is the amount of phosphorus present in 0.12g of organic compound

Hence, percentage of phosphorus