When CaO is added to water taken in a beaker, rise in temperature is observed. However, when Ba(OH)_(2) is mixed with NH_(4)Cl, a fall in temperature is observed. Why?

When CaO is added to water taken in a beaker, rise in temperature is o

1.	When CaO is added to water taken in a beaker, rise in temperature is observed. However, when Ba(OH)_(2) is mixed with NH_(4)Cl, a fall in temperature is observed. Why?
Answer» Solution :Reaction of CaO and water is an exothermic reaction. So, rise in temperature is observed. `UNDERSET("Calcium oxide")(CaO(s))+H_(2)O(l)rarrunderset("Calcium HYDROXIDE")(Ca(OH)_(2)(aq))+"Heat"` Reaction of `Ba(OH)_(2)andNH_(4)Cl` is an endothermic reaction and hence FALL in temperature is observed. `underset("hydroxide")underset("Barium")(Ba(OH)_(2))+underset("chloride")underset("Ammonium")(2NH_(4)Cl)+"Heat"rarrunderset("chloride")underset("Barium")(BaCl_(2))+underset("hydroxide")underset("Ammonium")(2NH_(4)OH)`