Question

Arrange the following in correct order of acidic strength:
$\left(I\right)C{H}_3-N{O}_2\left(II\right)N{O}_2-C{H}_2-N{O}_2\left(III\right)C{H}_3-C{H}_2-N{O}_2\left(IV\right)N{O}_2-CH\left(N{O}_2\right)-N{O}_2$

• A. IV > II > I > III
• B. IV > II > III > I
• C. III > I > II > IV
• D. III > I > IV > II

Answer 1

The correct option is A IV > II > I > III

$N{O}_2$ is an -I group, it will withdraw the electron toward itself. This will make ease to release the $H^{+}$ ion and the acidic strength will increase.
More the number of electron withdrawing group more will the acid strength. Thus (IV) has more acidic strength than (II) and (II) has more acidic strength than (I) and (III).
Comparing (I) and (III):
(III) is less acidic because it has $C{H}_3$ group which shows +I effect. Thus, it increase electron density so it least acidic.
Therefore, the correct order of acidic strength is
IV > II > I > III