Question

The number of species of the following that can act both as Bronsted acids and bases is $HCl , ClO _{4}^{-},{ }^{-} OH , H ^{+}, H _{2} O , HSO _{4}^{-}, SO _{4}^{2-}$, $H _{2} SO _{4}, Cl ^{-}$

• A. 4
• B. 3
• C. 1
• D. 2

Answer 1

The Correct Option is D

The correct answer is option (D): 2
(i) \(HCl \to H ^{+}+ Cl ^{-}\) (Bronsted acid) 
(ii) \(ClO _{4}^{-}+ H ^{+} \to HClO _{4}\) (Bronsted base) 
(iii) \(\bar{ O } H + H ^{+} \to H _{2} O\) (Bronsted base) 
(iv) \(H _{3} O ^{+} \to H ^{+}+ H _{2} O\) (Bronsted acid) 
(v) \(H ^{+}+ SO _{4}^{2-}\to HSO _{4}^{-}\) (Bronsted base) 
(vi) \(H _{2} SO _{4} \to H ^{+}+ HSO _{4}^{-}\) (Bronsted acid) 
(vii) \(Cl ^{-}+ H ^{+} \longrightarrow HCl\) (Bronsted base) 
Hence, \(H _{2} O\) and \(HSO _{4}^{-}\) (two species act as acid as well as base)