Question

consider the reaction below. hclo₃ + nh₃ → nh₄⁺ + clo₃⁻ which is a base-conjugate acid pair? ○ nh₃ and clo₃⁻ ○ nh₃ and nh₄⁺ ○ hclo₃ and nh₃ ○ hclo₃ and nh₄⁺

Explanation:

To identify a base - conjugate acid pair, we use the Bronsted - Lowry definition. A base is a proton ($\ce{H^{+}}$) acceptor, and its conjugate acid is the species formed when the base accepts a proton.

1. Analyze $\ce{NH_{3}}$: In the reaction $\ce{HClO_{3} + NH_{3}\to NH_{4}^{+} + ClO_{3}^{-}}$, $\ce{NH_{3}}$ accepts a proton ($\ce{H^{+}}$) to form $\ce{NH_{4}^{+}}$.
2. Check other options:

• For $\ce{NH_{3}}$ and $\ce{ClO_{3}^{-}}$, $\ce{NH_{3}}$ is a base and $\ce{ClO_{3}^{-}}$ is the conjugate base of $\ce{HClO_{3}}$, so they are not a base - conjugate acid pair.
• $\ce{HClO_{3}}$ is an acid (proton donor) and $\ce{NH_{3}}$ is a base (proton acceptor), they are not a conjugate pair.
• $\ce{HClO_{3}}$ is an acid and $\ce{NH_{4}^{+}}$ is a conjugate acid, they are not a conjugate pair.

So the base - conjugate acid pair is $\ce{NH_{3}}$ (base, proton acceptor) and $\ce{NH_{4}^{+}}$ (conjugate acid, formed by accepting a proton).

Answer:

B. $\ce{NH_{3}}$ and $\ce{NH_{4}^{+}}$