Answer and explanation;
- NH3 forms OH- ions by accepting H+ from H2O , while Ca(OH)2 forms OH- ions by ionizing.
That is, as shown by the equations below;
NH3 + H2O → NH4OH → NH4+ + OH-
Ca(OH)2 + H2O → Ca2+ + 2OH-
- As a Lewis base, NH3 has an electron lone pair that can attract hydrogen ion in the water, so NH3 + H2O—->(NH4)+ + (OH)- .
- On the other hand, Ca(OH)2 is a Bronsted base, so it can dissociate (OH)- itself. For Ca(OH)2, we have Ca(OH)2–>Ca2+ + 2(OH)-