There will be three moles of ions.
Because in an aqueous solution, HCl will break apart into H+ and Cl- ions.
HCl -> H+ + Cl−
1.5 HCl -> 1.5 H+ + 1.5 Cl−
So the aqueous solution will have 1.5 moles of hydrated hydrogen ions and 1.5 moles of hydrated chloride ions. So, a total of 3 moles of ions are present in the aqueous solution of 1.5 moles of HCl.
