Ans.) There are 8 moles of oxygen atoms in 2 moles of Na3PO4
One molecule of Na3PO4 contains 4 oxygen atom.
=> One mole of Na3PO4 molecule contain (1*4) mole oxygen atom
=> Two mole of Na3PO4 molecule contain (2*4) mole oxygen atom
So, 2 mole of Na3PO4 molecule contain 8 moles of oxygen atom
