The strongest acid among the following aromatic compounds is
| A. |
p-nitrophenol |
 |
| B. |
p-chlorophenol |
| C. |
p-cresol |
| D. |
m-nitrophenol |
Electron withdrawing groups like `—NO_2 , —Cl` stabilieses the phenoxide ion by dispersing negative charge, thus makes it more acidic. On the other hand electron releasing groups it more acidic. On the other hand electron releasing groups like `—CH_3` destabilises the phenoxide ion and thus make it less acidic.
`—NO_2` is more withdrawing as compared to `—Cl`. That's why pnitrophenol is most acidic among the given.