Question

Which type of substance yields hydrogen ions h in an aqueous solution?

Answer 1

Acids dissociate in water to release a proton. The proton then combines with water to form a  hydronium ion.  

HCl, hydrochloric acid dissociates in water to release proton H⁺ and chloride ion Cl⁻

HCl → H⁺ + Cl⁻

H⁺ + H₂O → H₃O⁺

Answer 2

Hydrogen-containing compounds that ionize to yield hydrogen ions (H+) in aqueous solution. Compounds that ionize to yield hydroxide ions (OH-) in aqueous solution.