In: Chemistry
Determine the pH of a solution created by mixing 240mL of 0.172M HCHO2 with 275.2mL of 0.150M NaOH.
The answer key says the answer is 8.32, but I keep getting 8.18
the Pka is missing for formic acid 3.75
HCHO2 + NaOH -------------> HCO2Na + H2O
240mL of 0.172M 275.2mL of 0.150M
41.28 41.28 complete neutralisation takes place so its a salt hydrolysis question
[salt ] =c = 41.28/515.2 = 0.080 M
pH = 7 + 1/2 Pka + 1/2logC = 7 + 1/2(3.75) + 1/2log(0.08) = 7 + 1.875 -0.548 = 8.327