Q.

By usual analysis, 1.00 g of compound (X) gave 1.79 g of magnesium pyrophosphate. The percentage of phosphorus in compound (X) is : ______ (nearest integer)

(Given, molar mass in g mol-1: O = 16, Mg = 24, P = 31)     [2026]

1 50  
2 30  
3 40  
4 20  

Ans.

(1)

% of P=nMg2P2O7×2×31W(unknown compound)×100

             =(1.79222×2×31)1×100

            =49.99%50%.