In general chemistry, what does the pH scale measure in an aqueous solution?

• A. The concentration of hydroxide ions, expressed as $pH=-\log \left(O^H\right)$
• B. The hydrogen ion concentration, expressed as $pH=-\log \left(H^{+}\right)$
• C. The temperature of the solution in degrees Celsius
• D. The total dissolved salt concentration (salinity) of the solution

Answer: (B)