Question 8.CC.5: Calculating pH Indicate if the pH values given for each the ......
Calculating pH
Indicate if the pH values given for each the following are correct or incorrect and why:
a. [{\mathrm H}_{3}{\mathrm O}^{+}]\,=\,1\,\times\,10^{-6}\,{\mathrm M} pH = -6.0
b. [{\mathrm H}_{3}{\mathrm O}^{+}]\,=\,1.0\,\times\,10^{-10}\,{\mathrm M} pH = 10
c. [{\mathrm H}_{3}{\mathrm O}^{+}]\,=\,1.0\,\times\,10^{-6}\,{\mathrm M} pH = 6.00
a. Incorrect. The pH of this solution is 6.0, which has a positive value, not negative.
b. Incorrect. This solution has a \left[H_{3}O^{+}\right] of 1.0\times10^{-10} M , which has a pH of 10.00. Two zeros are needed after the decimal point to match the two significant figures in the coefficient of the \left[H_{3}O^{+}\right] .
c. The pH is correctly calculated from the \left[H_{3}O^{+}\right] because there are two zeros after the decimal point to match the two significant figures in the coefficient of the molarity.