When Ba(OH)2 is mixed with NH4Cl then why BaCl2, NH3 and H2O is formed and not BaCl2 and NH4OH?
Forms aqueous ammonia (mind that ammonia is highly water soluble gas so no effervesence) and Barium Chloride which is water soluble.
Ba(OH)2 +2NH4Cl —->BaCl2 + 2NH3 +2H2O