Final answer:
A compound with a pH of 1 and complete ionization in solution is described as a strong acid, as it indicates a high concentration of hydrogen ions.
Step-by-step explanation:
The pH scale is used to determine the acidity or basicity of a solution. A compound with a pH of 1 in solution, where it has completely ionized, is highly acidic. Therefore, the correct answer to describe such a compound is c. Strong acid. Strong acids are 100% ionized in an aqueous solution, and a pH value as low as 1 indicates a very high concentration of hydrogen ions, which is characteristic of a strong acid. A compound with a pH of 1 in solution, where it has completely ionized, is a strong acid. Strong acids are substances that ionize completely in water to produce a high concentration of hydrogen ions (H+). Examples of strong acids include hydrochloric acid (HCl) and sulfuric acid (H2SO4).