Ionic Equilibrium Question 8
Question 8 - 30 January - Shift 2
The correct order of $pK_a$ values for the following compounds is:
(a)
(b)
(c)
(d)
(1) $c>a>d>b$
(2) $b>d>a>c$
(3) $b>a>d>c$
(4) $a>b>c>d$
Show Answer
Answer: (2)
Solution:
Formula: Formula
Due to $-M$ effect of $-NO_2$ group, it increases acidity
$+M$ effect of $N(CH_3)_2$ decreases acidity.
Hyperconjugation of isopropyl decrease acidity
$\therefore$ order of acidic strength
