* NH3 is a weak base: Ammonia (NH3) is a weak base. This means it reacts with water to produce hydroxide ions (OH-) which are responsible for making a solution basic (alkaline).

* Reaction with water: The reaction of ammonia with water is as follows:

NH3 (aq) + H2O (l) ⇌ NH4+ (aq) + OH- (aq)

* Increase in OH- concentration: This reaction results in the production of hydroxide ions (OH-), which increase the concentration of these ions in the solution.

* Higher pH: An increase in OH- concentration leads to a higher pH value, indicating a more basic solution.