The following equation shows the equilibrium in an aqueous solution of ammonia:NH3 (aq) + H2O (l) ⇌NH4 + (aq) + OH - (aq) Which of the following represents a conjugate acid-base pair? NH3 and H2ONH4 + and OH-H2O and OH-NH3 and

OH⁻ and H₂O

Explanation:

From the equation given in question,

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

Acids are the species which furnish hydrogen ions in the solution or is capable of forming bonds with electron pair species as they are electron deficient species.

When an acid donates a proton, it changes into a base which is known as its conjugate base.

Bases are the species which furnish hydroxide ions in the solution or is capable of forming bonds with electron deficient species as they are electron rich species. When a base accepts a proton, it changes into a acid which is known as its conjugate acid.

The acid and the base which is only differ by absence or presence of the proton are known as acid conjugate base pair.

Hence, from the equation given in the question,

The conjugate acid - base pair is -

OH⁻ and H₂O