When one of the following substances is dissolved in water, the only positive ions in the solution are hydrogen ions.
CH3OH
LiOH
PO4 -3
CO 3 -2
I wouldn't pick any of them.
CO3^2- + HOH == HCO3^- + OH^-
PO4^3- + HOH ==> HPO4^2- + OH^-
LiOH(aq) ==> Li^+ + OH^-
CH3OH ==> doesn't ionize with water.
One could argue that HCO3^- does ionize slightly to H^+ and CO3^2- and HPO4^2- ionizes slightly to H^+ + PO4^3- but I don't think that is what is meant by the problem.