Problem: The pKa of formic acid (HCOOH) is 3.74, a monoprotic weak acid. A 1.0 L sample of a buffer with a pH of 4.5 is combined with 0.09 moles of NaOH. What is the new pH of the solution? The ratio of HCOO- to HCOOH is 0.86 M to 0.15 M.

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FREE Expert Solution

Since we have a buffer we can use the Henderson-Hasselbalch Equation to calculate for pH. 

pH=pKa+logconjugate baseweak acid


pKa for formic acid (HCOOH) is given:  pKa = 3.74

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The pKa of formic acid (HCOOH) is 3.74, a monoprotic weak acid. A 1.0 L sample of a buffer with a pH of 4.5 is combined with 0.09 moles of NaOH. What is the new pH of the solution? The ratio of HCOO- to HCOOH is 0.86 M to 0.15 M.