Question

How many mole of Na ions are in 20 ml of 0.40 M of Na3PO4 ?

Answer 1

One molecule of Na3PO4contains 3 ions of Na+.

Molarity(M)=no.of moles(n)/Volume in litre (l)

⇒n=M×l=0.40M×0.02l=0.008moles

One ion of Na+ contribute 0.008 mol

So total moles of Na+ = 0.008×3=0.024moles(answer)