The ionization of ammonium ion is endothermic: NH4+(aq) + H2O(l)  NH3(aq) + H3O+(aq) ∆Hº > 0 Which — Acid-Base Chemistry Chemistry Question

The ionization of ammonium ion is endothermic:
NH⁴⁺(aq) + H₂O(l)  NH₃(aq) + H₃O⁺(aq) ∆Hº > 0
Which changes will result in the increase in [H₃O⁺] of a 0.100 M solution of NH₄Cl?
I. Diluting the solution from 1.00 L to 2.00 L
II. Raising the temperature from 25 ºC to 35 ºC