How many moles of magnesium phosphate `Mg_3 (PO_4)_2` will contain 0.25 mole of oxygen atoms ?

Options

A. 0.02
B. `3.125 xx 10^(-2)`
C. `1.25 xx 10^(-2)`
D. `2.5 xx 10^(-2)`

Answer

B

Explanation

1 mole of `Mg_(3)(PO_(4))_(2) rArr` 3 moles of Mg atom + 2 moles of P atom + moles of O atom
8 moles of oxygen atoms are present in = 1 mole of `Mg_(3)(PO_(4))_(2)`
0.25 mole of oxygen atoms are present in `= (1 xx 0.25)/(8) = 3.125 xx 10^(-2)` moles of `Mg_(3)(PO_(4))_(2)`