Which of the following is the pH when the concentrations of hydrogen ions and hydroxide ions in an aqueous solution are equal?
A. 14
B. 7
C. 1
D. 0
I think 1
To determine the pH when the concentrations of hydrogen ions (H+) and hydroxide ions (OH-) are equal, we need to recall the concept of pH and the self-ionization of water.
The pH scale measures the acidity or alkalinity of a solution. It ranges from 0 to 14, with 7 being considered neutral. A pH value less than 7 indicates acidity, while a pH value greater than 7 indicates alkalinity.
In an aqueous solution, water molecules can dissociate into hydrogen ions (H+) and hydroxide ions (OH-). This process is called self-ionization of water. The concentration of H+ ions multiplied by the concentration of OH- ions in any aqueous solution always equals a constant value, which is 1 x 10^-14 at 25 degrees Celsius.
In a neutral solution where the concentrations of H+ and OH- ions are equal, their concentrations would both be 1 x 10^-7 M. Therefore, the pH of a neutral solution at this concentration would be equal to -log(1 x 10^-7) which is 7.
So, in this case, the answer would be B. 7.