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

`underset("1 mole")(Mg_(3)(PO_(4))_(2))-=underset("8 mole")(8(O))`
8 mole of oxygen atoms are present in `Mg_(3)(PO_(4))_(2)=1` mole
0.25 mole of oxygen atoms are present in `Mg_(3)(PO_(4))_(2)`
`=(1xx0.25)/(8)=3.125xx10^(-2)` mole.