Answer:
Ammonium chloride has ammonium (NH4 +) part which is slightly acidic and Barium Hydroxide is a strong base.
You can see that an acid-base reaction will occur.
In this case :
Its highly endothermic reaction
Forms aqueous ammonia (mind that ammonia is highly water soluble gas so no effervesence) and Barium Chloride which is water soluble.
Ba(OH)2 +NH4Cl ——->BaCl2 + NH3 +H2O (unbalanced)
