Which equation correctly represents the relationship between pH and hydrogen ion concentration?

The relationship between pH and hydrogen ion concentration is indeed accurately given by the equation pH = -log[H+]. This equation expresses pH as the negative logarithm of the hydrogen ion concentration, where [H+] represents the concentration of hydrogen ions in moles per liter.

In this context, pH is a measure of the acidity or basicity of a solution, and it is defined such that lower pH values correspond to higher concentrations of hydrogen ions. The logarithmic scale means that each unit change in pH reflects a tenfold change in hydrogen ion concentration. For example, a solution with a pH of 3 has ten times the [H+] concentration of a solution with a pH of 4.

This relationship is fundamental in acid-base chemistry and is extensively used in biological systems, where maintaining appropriate pH levels is critical for enzyme activity and metabolic processes.

Other proposed equations do not accurately express this relationship. The incorrect options provide either an incorrect logarithmic relationship or misrepresent the variable roles, leading to confusion about how pH and hydrogen ion concentration interrelate.