wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

What is meant by buffer solutions?


Open in App
Solution

  1. The solutions which resist the change in pH on dilution or with the addition of small amounts of acid or alkali are called buffer solutions.
  2. It can be made are made in the following ways -
    I) Acidic buffer - Solution of a weak acid and its salt with a strong base.
    Example - Solution of acetic acid and its salt with a strong base i.e., Sodium acetate (CH3COONa).
    II) Basic buffer - Solution of a weak base and its salt with a strong acid.
  3. For example, a mixture of NH4Cl and NH4OH acts as a buffer at pH 9.25.
    NH4OH(l)NH4+(aq)+OH-(aq) (weakly ionized)
    NH4Cl(s)NH4+(aq)+Cl-(aq) (highly ionized)
    a) When we add a base (NaOH), OH- ions react with NH4+ ions to form feebly ionized NH4OH.
    So, pH remains constant as OH- ions concentration remains constant.
    NH4+(aq)+OH-(aq)NH4OH(l)
    b) If we add a few drops of acid (HCl),H+ ions from acid combine with NH4OH
    NH4OH(l)+H+(aq)NH4+(aq)+H2O(l)
  4. Thus, the addition of acid doesn't increase the pH as H+ ions concentration remains constant.

flag
Suggest Corrections
thumbs-up
1
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon