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Title: Can someone please help me calculate the pH of this solution? Post by: juelz on Apr 14, 2013 A solution of formic acid is titrated with NaOH until the solution is 0.45 M in formic acid and 0.55 M in sodium formate. Calculate the pH of this solution.
I think I'm supposed to use the Henderson-Hasselbalch equation, which in this case would be pH= pKa + log ([CH3COO-]/[CH3COOH]), but I'm not sure. If so, how would I calculate the pKa? Thanks in advance! Title: Can someone please help me calculate the pH of this solution? Post by: askaquestion on Apr 14, 2013 Yes, use the H-H equation. The pKa is a constant value. The value is 3.74 for formic acid.
pH = 3.74 + log (0.55/0.45) = 3.82 Title: Can someone please help me calculate the pH of this solution? Post by: julia.k18 on Apr 14, 2013 Henderson-Hasselbalch Equation:
pH= pKa + log([A-]/[HA]) pKa of formic acid is 3.698970004... so the value would make: pH= 3.70+ log (0.55/0.45) pH= 3.79 |