BUFFER SOLUTION – WORKING FOR ACIDIC AND BASIC BUFFER SOLUTION

by • 27/08/2013 • GeneralComments (0)375

BUFFER SOLUTION

A solution which resist against any change in its pH even after the addition of strong acid or base is called butter solution.

 

PREPARATION

A buffer solution can be prepared by mixing weak acid and salt of weak acid in same solution or weak base and salt of weak base in same solution i.e.

 

For Acid:

CH3COOH ======= CH3COO- + H+

CH3COONa ====== CH3COO- + Na+

 

For Base:

NH4OH ========= NH4 +OH-

NH4Cl =========  NH4 + Cl-

WORKING FOR ACIDIC BUFFER SOLUTION

Consider the example of acidic buffer solution, when strong base is added in the solution, the hydroxyl ion produce by base react with hydrogen ion already present in the solution to form water so that no change in pH occurs.

 

NaOH  <======>Na+ +OH-

OH-+ H+ <======> H2O

When strong acid is added in the solution the concentration of hydrogen ion increases in the container.

HCl ————-> H+ + Cl-

 

The increament in the no of hydrogen ions disturb the equilibrium of dissociation of weak acid so that a/c to be Le – Chatlier principle moves in backward direction to form undisclosed weak acid so that no extra H+ ions remain in the solution to change the pH of solution.

CH3COOH- + H’ ————-> CH3COOH

 

WORKING FOR BASIC BUFFER SOLUTION

Consider the example of basic buffer solution, when strong acid in the solution, the hydrogen ion produce by acid react with hydroxyl ion already present in the solution so that no change in pH occurs.

HCl <======> H+ + Cl-

OH-+ H+ <======> H20

 

When strong base is added in the solution the concentration of hydroxyl ions increases in the container.

NaOH <======> Na+ +OH-

 

The increament in the hydroxyl ion disturbs the equilibrium of dissociation of weak base so that a/c to be Le – Chatlier principle moves in backward direction to form undissolve weak base so that no extra OH ions remain in the solution to change the pH of solution.

NH4OH <======> NH4 +OH-

Affection with those childlike caresses which http://www.essaynara.com/ are the bent of every
Pin It

Leave a Reply