Which of the following phenol is strongest acid

1.	Which of the following phenol is strongest acid
Answer» Solution :Presence of `-NO_(2)` group at o-or p-positions to `-OH` group make it is stronger acid than when `-NO_(2)` groups is at m-position. This 'B' and 'D' are stronger ACIDS than 'A' and 'C'. In 'D' the `NO_(2)` groups is flasked by two `-CH_(3)` groups which push the `NO_(2)` group out of plane of the BENZENE ring. As a result of this steric hinderance, the electron withdrawing resonance effect of the `-NO_(2)` group will be reduced and as such 'D' will be a WEAKER acid than 'B'. Therefore 'B' is the STRONGEST acid.

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