Question 10.5: Calculate the pH for each of the following solutions. a. [H3......

General, Organic, And Biological Chemistry [1102665]

Calculate the pH for each of the following solutions.

a. [H $_{3}O^{+}$ ] = 7.23 × 10 $^{-8}$ b. [H $_{3}O^{+}$ ] = 5.70 × 10 $^{-3}$

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a. Using an electronic calculator, first enter the number 7.23 × 10 $^{-8}$ into the calculator.
Then use the LOG key to obtain the logarithm value, -7.1408617. Changing the sign of this number (because of the minus sign in the definition of pH) and adjusting for significant figures yields a pH value of 7.141.
b. Entering the number 5.70 × 10 $^{-3}$ into the calculator and then using the LOG key give a logarithm value of -2.2441251. This value translates into a pH value, after rounding, of 2.244.

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