Simple wording prepared by Ali Zia

2. Topic
Acidity Of Carboxylic Acid

3. Presented By
Ali Zia

4. Presented To
Mam Samman Arshad

5. Table Of Contents
• Acidity Of Carboxylic Acid
• Acidity Constant
• Effects of Substituent on acidity of Carboxylic Acid

6. Acidity Of Carboxylic Acid
• The distinctive chemical feature of the carboxylic acids is
their acidity which merits a detailed discussion.
• In an aqueous solution, molecules of these acids
interact with water molecules to form carboxylate
ions and hydronium ions.

7. Acidity Of Carboxylic Acid

8. Acidity Of Carboxylic Acid
• As indicated above, most simple carboxylic acids are only
slightly ionized in water and these are fairly weak acids.
• A 1 molar solution of acetic acid is ionized only to about
05% at room temperature white a strong acid like
hydrochloric acid or sulphuric acid is almost completely
ionized.

9. Acidity Of Carboxylic Acid
• Evidently water molecules are not very strong
proton acceptors in relation to carboxylic acids,
which are relatively weak proton donors.

10. Acidity Constant
• The ionization or dissociation equilibrium of a carboxylic
acid, similar to inorganic acids, may be simply written as

11. Acidity Constant
• Where H+ represents a hydronium ion H3O.
• Applying the Mass Law, the dissociation constant or
acidity constant K, for the above equilibrium can be
expressed as

13. Acidity Constant
• The value of K. which is directly proportional to the
concentration of hydrogen ions, is thus a measure of
acidity of the individual acid under consideration. The
larger the value of K. the greater the concentration of H
ions and stronger the acid.

14. Acidity Constant
• For example the value of K. for acetic acid is 1'8 x lO
while that for HCI is 10. Thus acetic acid is a much
weaker acid than hydrochloric acid. The value of K. for
ethyl alcohol is lO which has far low acidity compared to
even acetic acid.

21. Refrences
• Courtesy by the book of Organic Chemistry