Which reactions show an oxide acting as a base?
Check all that apply.

K2O(s)+H2O(l)→2K+(aq)+OH−(aq)
SO3(l)+H2O(l)→ H+(aq)+HSO4−(aq)
Al2O3(s)+6OH−(aq)+3H2O(l)→2Al(OH)−4(aq)
Al2O3(s)+6H+(aq)→2Al3+(aq)+3H2O(l)
SiO2(s)+2OH−(aq)→ SiO3−(aq)+H2O(l)
MgO(s)+2H+(aq)→Mg2+(aq)+H2O(l)