Which of the following solutions that have concentrations of $0.01\ \mathrm{M}$ show the highest elevation in boiling point and why?
A) $\ce{NaCl}$
B) $\ce{CaCl2}$
C) $\ce{H3PO4 }$
D) $\ce{C6H12O6}$ (glucose)
When dissolved in water, $\ce{H3PO4 }$ dissociates into 4 ions, which is more than any of the other compounds. Someone told me though, that because it's a weak-acid, it doesn't matter how many ions it has, and that $\ce{CaCl2}$ will still have the highest elevation boiling point. Is this true?