Q. 10.8 - An Introduction to General, Organic, and Biological Chemistry

Question

Identify the reactant that is a Brønsted-Lowry acid and the reactant that is a Brønsted-Lowry base in each of the following:

a. ${\mathrm{CO}}_3{}^{2-}(aq)+{\mathrm{H}}_2\mathrm{O}(l)\rightleftarrows {\mathrm{HCO}}_3{}^{-}(aq)+{\mathrm{OH}}^{-}\left(aq\right)$

b. ${\mathrm{H}}_2{\mathrm{SO}}_4\left(aq\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)⟶{\mathrm{HSO}}_4^{-}\left(aq\right)+{\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)$

Step-by-Step Solution

Answer

(Part a)${\mathrm{CO}}_3{}^{2-}$is Bronsted Lowry base and ${\mathrm{H}}_2\mathrm{O}$ is Bronsted Lowry acid.

(Part b)  ${\mathrm{H}}_2\mathrm{O}$ is Bronsted Lowry base and ${\mathrm{H}}_2{\mathrm{SO}}_4$ is Bronsted Lowry acid.

Step 1- Introduction & information (part a)

Bronsted Lowry acid-base system:  

Acid: 

According to Bronsted Lowry; Acids are substances that donate ${\mathrm{H}}^{+}$ (hydrogen ions) or protons. Usually Bronsted-Lowry acid is  the  proton donor.

 

Base:

 According to Bronsted Lowry; A base is a substance that accepts ${\mathrm{H}}^{+}$ (hydrogen ions) or protons. In general, Brønsted-Lowry bases are proton acceptors.

$\mathrm{HF}+{\mathrm{NH}}_3\to {\mathrm{NH}}_4^{+}+{\mathrm{Cl}}^{-}$

Acid     base

Step 2- Information (part b)

Acid-Base Neutralization: 

When an acid reacts with a base to form an ionic salt with water or a solvent, this reaction is called an acid-base neutralization reaction. 

$\mathrm{HCl}\left(aq\right)+\mathrm{KOH}\left(aq\right)\to {\mathrm{H}}_2\mathrm{O}\left(l\right)+\mathrm{KCl}\left(aq\right)$

    Acid          Base             Water        Salt

Step 3- Explanation (part a)

a.

In this reaction, ${\mathrm{H}}_2\mathrm{O}$ is Bronsted-Lowry acid giving ${\mathrm{H}}^{+}$ (hydrogen ions) or protons.

 ${\mathrm{CO}}_3^2$ is a Bronsted-Lowry base that  accepts  ${\mathrm{H}}^{+}$(hydrogen ions) or protons.

${\mathrm{H}}_2\mathrm{O}\left(l\right)+{\mathrm{CO}}_3^{2-}\left(aq\right)\rightleftharpoons {\mathrm{HCO}}_3^{-}\left(aq\right)+{\mathrm{OH}}^{-}\left(aq\right)$

   Acid         Base

Step 4- Explanation (part b)

b.

In this reaction, ${\mathrm{H}}_2{\mathrm{SO}}_4$  is Bronsted-Lowry acid, ${\mathrm{H}}^{+}$ (hydrogen ion) or proton.

${\mathrm{H}}_2\mathrm{O}$ is a Bronsted-Lowry base that  accepts ${\mathrm{H}}^{+}$ (hydrogen ions) or protons.

${\mathrm{H}}_2{\mathrm{SO}}_4\left(aq\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\to {\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)+{\mathrm{HSO}}_4^{-}\left(aq\right)$

    $Acid Base$