Question

Household ammonia is a solution of the weak base NH₃ in water. List, in order of descending concentration, all of the ionic and molecular species present in a 1-M aqueous solution of this base.

a) NH₄⁺, NH₃, H₂O
b) NH₃, NH₄⁺, OH⁻
c) NH₄⁺, NH₃, H⁺
d) H⁺, OH⁻, NH₃

Answer 1

In a 1-M ammonia solution, the species present in descending concentration are ammonia (NH3), water (H2O), ammonium ion (NH4+), and hydroxide ion (OH−) as ammonia is a weak base that partially dissociates in water. option (B)

Step-by-step explanation:

Household ammonia (NH3) is a solution of a weak base dissolved in water. When ammonia is in an aqueous solution, it predominantly remains as NH3 molecules, but a small fraction reacts with water to form ammonium ions (NH4+) and hydroxide ions (OH−). Given that ammonia is a weak base and only a small portion dissociates, the species present in a 1-M aqueous solution of ammonia will be, in order of descending concentration:

Thus, the correct listing in order of descending concentration is b) NH3, H2O, NH4+, OH−.