What is the concentration of hydrogen ions in water with a pH of 7?

What is the concentration of hydrogen ions in water with a pH of 7?

• A. Ten to the seventh power times M
• B. Seven times M
• C. Point seven times M
• D. Ten to the negative seven times M

Answer: (D)

A pH of 7 indicates a neutral solution, which is characteristic of pure water at 25 degrees Celsius. The pH scale is logarithmic; specifically, pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration. This means that a pH of 7 corresponds to a hydrogen ion concentration of 1 x 10^(-7) M (molar). Thus, when the pH is 7, it directly translates to a concentration of hydrogen ions being 10 to the negative seventh power times M, reflecting a neutral state. This concept aligns with the understanding that each unit change in pH represents a tenfold difference in hydrogen ion concentration. Therefore, a pH of 7 signifies a hydrogen ion concentration of 0.0000001 M, or 10^(-7) M, confirming the accuracy of the answer provided.

A pH of 7 indicates a neutral solution, which is characteristic of pure water at 25 degrees Celsius. The pH scale is logarithmic; specifically, pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration. This means that a pH of 7 corresponds to a hydrogen ion concentration of 1 x 10^(-7) M (molar).

Thus, when the pH is 7, it directly translates to a concentration of hydrogen ions being 10 to the negative seventh power times M, reflecting a neutral state. This concept aligns with the understanding that each unit change in pH represents a tenfold difference in hydrogen ion concentration. Therefore, a pH of 7 signifies a hydrogen ion concentration of 0.0000001 M, or 10^(-7) M, confirming the accuracy of the answer provided.