Weight of organic compound = 0.33g ;
Weight of Mg2P2O7 = 0.397g
222 g of Mg2P2O7 contains 62 g of phosphorous.
0.397 g of Mg2P2O7 will contain \(\frac{62}{222}\) x 0.397 g of P
0.33 g of organic compound contains \(\frac{62}{222}\) x \(\frac{0.397}{0.33}\) g of P
100 g of organic compound will contain \(\frac{62}{222}\) x \(\frac{0.397}{0.33}\) x 100
= \(\frac{2461.4}{73.26}\) = 33.59%
Percentage of phosphorous = 33.59 %