Q. How many moles of magnesium phosphate, ${Mg}_{3}\left( {PO}_{4} \right)_{2}$ will contain 0.25 mole of oxygen atoms?
A) 0.02
B) $3.125 \times 10^{- 2}$
C) $1.25 \times 10^{- 2}$
D) $2.5 \times 10^{- 2}$
Explanation
(b)
${Mg}_{3}\left( {PO}_{4} \right)_{2};mole\$
8 mole of O-atom are contained by 1 mole ${Mg}_{3}\left( {PO}_{4} \right)_{2}.$
Hence, 0.25 moles of O-atom $= \frac{1}{8}\ \times 0.25\ mole\ {Mg}_{3}\left( {PO}_{4} \right)_{2}$
$= \ 3.125 \times 10^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.