Identifying Acids and Bases

The general steps for identifying whether a common substance is a strong acid, a weak acid, a strong base, or a weak base are below.

Step #1: Identify the substance as an Arrhenius acid or base using the following criteria.

• The names of the acids end in “acid”. Acid formulas have one of these forms: HX(aq) or H_aX_bO_c.
• Ionic compounds that contain hydroxide (OH^-) , carbonate (CO₃^2-) , or hydrogen carbonate (HCO₃^-) anions are basic. Ammonia, NH₃, is also a base.

Step #2: If the substance is an acid or base, determine whether it is strong or weak.

• All common acids except HCl(aq), HNO₃, and H₂SO₄ are weak.
• All common bases except metal hydroxides are weak.