To determine the acid-conjugate base pair in the given chemical reaction:
[tex]\[ NH_4^+ + H_2O \rightarrow NH_3 + H_3O^+ \][/tex]
we need to understand the concept of conjugate acid-base pairs. A conjugate acid-base pair consists of two species that differ by only one proton (H^+).
In the reaction provided:
- [tex]\( NH_4^+ \)[/tex] (ammonium ion) loses a proton ([tex]\( H^+ \)[/tex]) to become [tex]\( NH_3 \)[/tex] (ammonia).
- [tex]\( NH_4^+ \)[/tex] is the conjugate acid, while [tex]\( NH_3 \)[/tex] is the conjugate base of [tex]\( NH_4^+ \)[/tex].
To confirm, let's analyze the other options:
- [tex]\( NH_4^+ \)[/tex] and [tex]\( H_3O^+ \)[/tex]: These do not differ by a single proton. [tex]\( NH_4^+ \)[/tex] is an ammonium ion, and [tex]\( H_3O^+ \)[/tex] is a hydronium ion, which are entirely different species.
- [tex]\( H_2O \)[/tex] and [tex]\( NH_3 \)[/tex]: Similarly, these do not constitute a conjugate acid-base pair because [tex]\( NH_3 \)[/tex] is ammonia and [tex]\( H_2O \)[/tex] is water; they do not differ by just one proton.
- [tex]\( H_2O \)[/tex] and [tex]\( H_3O^+ \)[/tex]: This is indeed a conjugate acid-base pair. [tex]\( H_2O \)[/tex] (water) accepts a proton to form [tex]\( H_3O^+ \)[/tex] (hydronium ion). However, as per the reaction given specifically involving [tex]\( NH_4^+ \)[/tex] and [tex]\( NH_3 \)[/tex], this pair is not the one mainly highlighted in the context of the reaction provided.
Based on the reaction provided, the relevant acid-conjugate base pair is:
[tex]\[ NH_4^+ \text{(acid)} \rightarrow NH_3 \text{(conjugate base)} \][/tex]
Thus, the correct answer is:
[tex]\( NH_4^+ \)[/tex] and [tex]\( NH_3 \)[/tex]
So, the correct choice number is:
1. [tex]\( NH_4^+ \)[/tex] and [tex]\( NH_3 \)[/tex]
