Question

Which is stronger acid in the following pair?
$2$-Nitrophenol and $2,4,6$-Trinitrophenol.

Answer 1

2,4,6 -Trinitrophenol is more acidic than the 2- Nitrophenol because a compound is more acidic if it can easily release H+ in the solution. $N{O}_2$ has an electron withdrawing effect and pulls the electron density towards itself. Since, 2,4,6 -Trinitrophenol contains Three $N{O}_2$ groups in comparison to one in 2- Nitrophenol. Hence 2,4,6 -Trinitrophenol has greater tendency to attract electrons towards itself and hence more acidic than 2-Nitrophenol.