Arrhenius, Br??nsted-Lowry and Lewis Concepts — Prelims Questions

Which of the following statements is INCORRECT regarding the Brønsted-Lowry concept of acids and bases?

Identify the conjugate base of $H_2PO_4^-$ in an aqueous solution.

Which of the following species can act as both a Brønsted-Lowry acid and a Brønsted-Lowry base (i.e., is amphiprotic)?

Which of the following is the strongest Lewis acid?

Consider the reaction: $H_2S(aq) + CN^-(aq) \rightleftharpoons HS^-(aq) + HCN(aq)$. Identify the Brønsted-Lowry acids and bases in this equilibrium.

Which of the following is an example of a Lewis acid but NOT a Brønsted-Lowry acid?