In: Chemistry
Calculate the pH during the titration of 40.00 mL of 0.1000M propanoic acid (HPr; Ka=1.3x10-5) after adding 22.18 mL of 0.1000M NaOH.
** All volumes should have a minimum of 2 decimal places
Given 40 mL of 0.1 M CH3CH2COOH and 22.18 mL of 0.1 M NaOH
Moles of CH3CH2COOH = 0.04 L x 0.1 = 0.004 moles
Moles of NaOH = 0.02218 L x 0.1 = 0.002218 moles
NaOH + CH3CH2COOH -------- H20 + NaCH3CH2COO
0.002218 0.004 0 initially
0 0.004-0.002218 0.002218 finally
Now pH = pKa + log [NaCH3CH2COO] / [CH3CH2COOH ]
given Ka =1.3 x 10-5 from this pKa = - log Ka = 4.886
Therefore pH = 4.886 + log 0.002218/ 0.001782 = 4.886 + 0.095 = 4.98 which is acidic solution