For an aqueous solution,the characteristic species of acid is

The conjugate acid of $NH_2^-$ is

In the equilibrium $HClO_4 + H_2O \rightleftharpoons H_3O^{+} + ClO_4^-$,which of the following statements is correct?

Ammonia is a Lewis base because it is

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:

What is the aqueous solution of $HCl$ known as?