Which of the following cannot act both as Bronsted acid and as Bronsted base?

(1)  HSO₄^–

(2)  HCO₃^–

(3) NH₃

 (4) HCl

Correct Answer: (4) HCl

Explanation: The substance which can release and accept H+ can act as both Bronsted base and acid. HCl cannot accept H+ therefore cannot act as Bronsted base