Question

A buffer contains significant amounts of ammonia and ammonium chloride.

Answer 1

Answer:

a. HCl + NH₃ ⇄ NH₄Cl

b. KOH + NH₄⁺ ⇄ K⁺ + NH₃ + H₂O

Explanation:

A buffer system is made by a weak base (ammonia, NH₃) and its conjugate acid (ammonium ion NH₄⁺ coming from ammonium chloride NH₄Cl). Its function is to resist abrupt changes in the pH when acids or bases are added.

a. When aqueous hydrochloric acid is added, it reacts with the base of the buffer. The corresponding equation is:

HCl + NH₃ ⇄ NH₄Cl

b. When aqueous potassium hydroxide is added, it reacts with the acid of the buffer. The corresponding equation is:

KOH + NH₄⁺ ⇄ K⁺ + NH₃ + H₂O