Advices For Studying Organic Chemistry

pKa = 4.75 pKa = 2.86

1) The extra electron-withdrawing inductive effect of the electronegative chlorine

atom is responsible for the greater acidity of chloroacetic acid by making the

hydroxyl proton of chloroacetic acid even more positive than that of acetic acid.

2) It stabilizes the chloroacetate ion by dispersing its negative charge.

CO

O

CH 2 < <

<

< < <

<

Cl H ++H 2 OH< <COG− 3 O+

O

Cl CH 2

G−

G−

Figure 3.10 The electrostatic potential maps for acetate and chloroacetate ions
show the relatively greater ability of chloroacetate to disperse the
negative charge.

3) Dispersal of charge always makes a species more stable.

4) Any factor that stabilizes the conjugate base of an acid increases the

strength of the acid.