Which of the following salts is acidic?

The species: $H_{2}O$,$HCO_{3}^{-}$,$HSO_{4}^{-}$,and $NH_{3}$ can act both as Bronsted acids and bases. For each case,give the corresponding conjugate acid and conjugate base.

According to the Bronsted-Lowry concept,an acid is a substance which:

Which of the following acts as a base according to the $Brønsted-Lowry$ theory?

What is meant by the conjugate acid-base pair? Find the conjugate acid/base for the following species: $HNO_2, CN^{-}, HClO_4, F^{-}, OH^{-}, CO_3^{2-}$ and $S^{2-}$

Which of the following statements is true?