question_answer

The correct order of acidity of following acids is

A) \[>-Cl-C{{H}_{2}}COOH>HCOOH>C{{H}_{3}}COOH\]

B) \[F-C{{H}_{2}}COOH>Cl-C{{H}_{2}}COOH\]

C) \[HCOOH>C{{H}_{3}}COOH>Cl-C{{H}_{2}}COOH\]

D) None of the above

Correct Answer: A

Solution :

Group or atom attached with \[-COOH\] group shows positive inductive effect increases electron density on oxygen atom, which suppress the ionization of\[{{H}^{+}}\], hence, acidic strength decreases. Group or atom attached with \[-COOH\] group shows negative inductive effect decreases electron density on oxygen atom, which facilitate the ionization of\[{{H}^{+}}\], hence acidic strength increases. Sequence of group shows negative inductive effect.                 \[-CHC{{l}_{2}}>C{{H}_{2}}F>-C{{H}_{2}}Cl\] \[-C{{H}_{3}}\]group shows positive inductive effect and \[-H\] doesnt show any effect. So, \[>ClC{{H}_{2}}COOH>HCOOH>C{{H}_{3}}COOH\]