Dear student
The reaction taking place between Barium hydroxide and Ammonium chloride is an endothermic reaction, which is characterised by a fall in temperature. The products formed are Barium chloride, water and Ammonia gas is released during the reaction.
Ba(OH)2 (aq) + 2NH4Cl(aq) BaCl2(aq) + 2H2O(l) + 2NH3(g)
Regards