Q. 10.13 - An Introduction to General, Organic, and Biological Chemistry

Question

Identify the Brønsted-Lowry acid-base pairs in each of the following equations:

$$\begin{gathered} a) H_{2}C{O}_3(aq)+H_{2}O(l)\rightleftarrows HC{O}_3^{-}(aq)+H_3{O}^{+}(aq\left) \\ b\right) N{H}_3^{+}\left(aq\right)+H_{2}O\left(l\right)\rightleftarrows N{H}_3\left(aq\right)+H_3{O}^{+}\left(aq\right) \\ c) HCN(aq)+N{O}_2^{-}(aq)\rightleftarrows C{N}^{-}(aq)+HN{O}_2(aq) \end{gathered}$$

Step-by-Step Solution

Answer

(Part a) The conjugate acid-base pairs are $H_{2}C{O}_3$ and $HC{O}_3^{-}$ along with $H_{2}O$ and $H_3{O}^{+}$.

(Part b) The conjugate acid-base pairs are $N{H}_4^{+}$ and $N{H}_3$ along with $H_{2}O$ and $H_3{O}^{+}$ 

(Part c)  The conjugate base-acid pairs are $HCN$ and $C{N}^{-}$ along with $N{O}_2^{-}$ and $HN{O}_2$

Step 1: Introduction (Part a)

Given are the chemical equations, to find Brønsted-Lowry acid-base pairs in each of the given equations 

Step 2: explanation of (Part a)

 In the reaction,$H_{2}C{O}_3$ donates $H^{+}$ to $H_{2}O$. The resulting $HC{O}_3^{-}$ is the conjugate base and $H_3{O}^{+}$ the conjugate acid. The conjugate acid-base pairs are $H_{2}C{O}_3$ and $HC{O}_3^{-}$ along with  $H_{2}O$ and  $H_3{O}^{+}$.

Step 3: explanation of (Part b)

(b) In the reaction, $N{H}_4^{+}$ donates $H^{+}$ to $H_{2}O$. The resulting $N{H}_3$ is the conjugate base and $H_3{O}^{+}$ the conjugate acid. The conjugate acid-base pairs are $N{H}_4^{+}$ and $N{H}_3$ along with $H_{2}O$ and $H_3{O}^{+}$

Step 4: explanation of (Part c)

In the reaction, $HCN$ donates $H^{+}$ to $N{O}_2^{-}$. The resulting $C{N}^{-}$is the conjugate base and $HN{O}_2$ the conjugate acid. The conjugate base-acid pairs are $HCN$ and $C{N}^{-}$along with $N{O}_2^{-}$ and $HN{O}_2$