Question

Which of the following behaves as Lewis acid and not as Bronsted acid ?

• A. $HCl$
• B. $H_2SO_4$
• C. $HSO_3^-$
• D. $SO_3$

Answer 1

Answer: (D)

Lewis acids have a tendency to accept electrons while Bronsted acids have a tendency to donate proton.

(a) $\underset {\text{Bronsted acid}}{HCl} \longrightarrow H ^{+}+ Cl ^{-}$

(b) $\underset{\text{Bronsted acid}}{H _{2} SO _{4}} \longrightarrow H ^{+}+ HSO _{4}^{-}$

(c) $\underset{\text{Bronsted acid }}{HSO _{3}^{-}} \longrightarrow H ^{+}+ SO _{3}^{2-}$