WHich of the following solutions of strong electrolytes contain the largest number of ions?

Question

100.0 ml of 0.100 M NaOH

50.0 mL of 0.200 M BaCl2

75.0 mL of 0.150 M Na3PO4

Answer 1

50.0 mL of 0.200 M BaCl2

Answer 2

Number of moles of particles = Molarity*Volume in litres

Number of moles of NaOH= 0.100 M * 0.100 L = 0.0100 mol NaOH

Each mole of NaOH has one mole Na+ ions and 1 mol OH- ions

So 0.0100 mol NaOH has a total of 0.0100 + 0.0100 = 0.0200 mol ions

Number of moles of BaCl2 = 0.200 M * 0.050 L = 0.0100 mol BaCl2

Each mol BaCl2 has 1 mol Ba2+ ions and 2 mol Cl- ions

So 0.0100 mol BaCl2 has 0.0100 + 2*0.0100 = 0.0300 mol ions

Number of moles of Na3PO4 = 0.150 M * 0.075 L = 0.01125 mol Na3PO4

0.01125 mol Na3PO4 contains 3*0.01125 + 0.01125 = 0.045 mol ions

Thus, 75 mL of 0.150 M Na3PO4 contains the largest number of ions