Which of the following is not a Lewis acid?

Which of the following is not a Lewis base?

Classify the following species as Lewis acids or Lewis bases: $CO_2$,$BCl_3$,$NH_3$,$CH_3NH_2$,$NO_2^+$,and $C_6H_5NH_3^+$.

In the following reaction $HCO_3^{-} + H_2O \rightleftharpoons CO_3^{2-} + H_3O^{+}$,which two substances are Bronsted bases?

The $pK_a$ of acetylsalicylic acid (aspirin) is $3.5$. If the $pH$ of human stomach fluid is $2-3$ and the $pH$ of the small intestine fluid is $8$,then aspirin will:

Identify the conjugate acid-base pair in the following reaction.
$H_2O + HCl \rightarrow H_3O^{+} + Cl^{-}$