In the acid-base reaction between ammonia and water, which of the following substances are present at equilibrium?
A) Ammonia, water, ammonium, and hydroxide are all present at equilibrium.
B) Only ammonia and water are present at equilibrium.
C) Only ammonium and hydroxide are present at equilibrium.
D) Only hydroxide and hydronium are present at equilibrium.
E) It is not possible to say which molecules will be present at equilibrium.

Question

In the acid-base reaction between ammonia and water, which of the following substances are present at equilibrium? 
A) Ammonia, water, ammonium, and hydroxide are all present at equilibrium. 
B) Only ammonia and water are present at equilibrium. 
C) Only ammonium and hydroxide are present at equilibrium. 
D) Only hydroxide and hydronium are present at equilibrium. 
E) It is not possible to say which molecules will be present at equilibrium.

Quizplus · Accepted Answer

In the acid-base reaction between ammonia and water, ammonia acts as a base and water acts as an acid. The reaction can be written as:
NH3 + H2O ⇌ NH4+ + OH-
At equilibrium, all four molecules (ammonia, water, ammonium, and hydroxide) will be present in some amounts, hence choice A is the correct answer.

In the Acid-Base Reaction Between Ammonia and Water, Which of the Following