What is the Difference Between Buffer Solution and Salt Hydrolysis

The key difference between buffer solution and salt hydrolysis is that buffer solutions are solutions that can resist any change to their pH value to some certain extent, whereas salt hydrolysis is a chemical reaction that can change the pH of a solution.

A buffer is an aqueous solution that tends to resist the change in pH. Salt hydrolysis is a reaction having one of the ions from a salt reacting with water, forming either an acidic or basic solution.

CONTENTS

1. Overview and Key Difference
2. What is Buffer Solution  
3. What is Salt Hydrolysis 
4. Buffer Solution vs Salt Hydrolysis in Tabular Form
5. Summary – Buffer Solution vs Salt Hydrolysis

What is Buffer Solution?

A buffer is an aqueous solution that tends to resist the change in pH. This solution contains a mixture of a weak acid and its conjugate base or vice versa. The pH of these solutions changes slightly upon the addition of either a strong acid or a strong base.

The weak acid (or base) and its conjugate base (or conjugate acid) are in equilibrium with each other. If we add some strong acid to this system, the equilibrium shifts towards the acid, and it forms more acid using the hydrogen ions released from the added strong acid. Although we expect an increase of the hydrogen ions upon the addition of the strong acid, it doesn’t increase that much. Similarly, if we add a strong base, the hydrogen ion concentration decreases by less than the amount expected for the quantity of alkali added. We can measure this resistance to pH changes as the buffer capacity. The buffer capacity measures the resistance of a buffer to pH change on the addition of OH– ions (a base).

When considering the applications of buffers, these solutions are necessary to keep the correct pH for enzymatic activity in organisms. Moreover, these are used in industries in the fermentation processes, setting the correct conditions for dyes, in chemical analysis, calibrating pH meters, etc.

What is Salt Hydrolysis?

Salt hydrolysis can be described as a reaction having one of the ions from a salt that reacts with water, forming either an acidic or basic solution. If a particular salt is formed from the neutralization reaction between a weak acid and a strong base, it will always produce salt solutions that are basic when it undergoes salt hydrolysis. On the other hand, if a particular salt is formed from the neutralization reaction between a strong acid and a weak base, it will always produce basic salt solutions upon salt hydrolysis. Similarly, if a neutralization occurs between a strong acid and a strong base, the resultant salt solution will have pH 7 (neutral solution) upon salt hydrolysis. This means neutral salt solutions do not undergo salt hydrolysis.

The salt hydrolysis reaction can be described as a reverse neutralization. If we add a salt to the water, the cation, anion, or both ions of the salt tend to react with water, resulting in either a basic or an acidic solution upon hydrolysis process.

What is the Difference Between Buffer Solution and Salt Hydrolysis?

Buffer solutions and salt hydrolysis are important terms in inorganic and analytical chemistry. The key difference between buffer solution and salt hydrolysis is that buffer solutions are solutions that can resist any change to their pH value to some certain extent, whereas salt hydrolysis is a chemical reaction that can change the pH of a solution.

Below is a summary of the difference between buffer solution and salt hydrolysis in tabular form for side by side comparison.

Summary – Buffer Solution vs Salt Hydrolysis

A buffer is an aqueous solution that tends to resist the change in pH. Salt hydrolysis is a reaction having one of the ions from a salt that reacts with water, forming either an acidic or basic solution. The key difference between buffer solution and salt hydrolysis is that buffer solutions are solutions that can resist any change to their pH value to some certain extent, whereas salt hydrolysis is a chemical reaction that can change the pH of a solution.

Reference:

1. “21.21: Hydrolysis of Salts- Equations.” Chemistry LibreTexts, Libretexts, 22 Feb. 2022.

Image Courtesy:

1. “Buffer Capacity 2” By Quantumkinetics – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Electrolysis” By © Nevit Dilmen (CC BY-SA 3.0) via Commons Wikimedia