Which of the following is a Lewis acid?

Which one of the following is the most basic?

Explain acid-base and their types according to $(A)$ Arrhenius and $(B)$ Bronsted-Lowry with examples.

Which are the bases of the above reaction $HCl_{(aq)} + H_2O_{(aq)} \rightleftharpoons H_3O^{+}_{(aq)} + Cl^{-}_{(aq)}$? Which base is weak?

Consider the following reaction involving two acids shown below: formic acid and $HF$.
$K^+F^- + HCOOH \rightleftharpoons HCOO^-K^+ + HF$
Given: $pK_a$ of $HCOOH = 3.8$ and $pK_a$ of $HF = 3.2$.
Which of the following statements about this reaction are true?
$(A)$ Formic acid is the strongest Bronsted acid in the reaction
$(B)$ $HF$ is the strongest Bronsted acid in the reaction
$(C)$ $KF$ is the strongest Bronsted base in the reaction
$(D)$ $KO_2CH$ is the strongest Bronsted base in the reaction
$(E)$ The equilibrium favours the reactants
$(F)$ The equilibrium favours the products
$(G)$ Formic acid has a weaker conjugate base
$(H)$ $HF$ has a weaker conjugate base

The Bronsted acids in the reversible reaction are $HCO_3^- (aq) + OH^- (aq) \rightleftharpoons CO_3^{2-} (aq) + H_2O (l)$