I was wondering what the answer for this question would be ?

C. H2O is the base and H3O+ is the conjugate acid

Explanation:

According to Bronsted-Lowry acid-base theory, an acid is a substance that loses an hydrogen ion or proton (H+) while a base is a substance that gains an hydrogen ion (H+) or proton. Furthermore, this theory states that, the molecule formed when an acid donates its proton is called the CONJUGATE BASE, while the molecule formed when the base accepts proton is called CONJUGATE ACID.

In this question, the following equation is given:

NH4+(aq) + H2O(aq) ⇌NH3(aq) + H3O+ (aq)

Water (H2O) is the base in this equation because according to Bronsted-Lowry acid-base theory, it accepts an hydrogen ion (H+) while hydroxonium ion (H3O+) is the conjugate acid.

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