In: Chemistry
The pH of a solution prepared by dissolving 0.350 mol of acetic acid (CH3CO2H) in 1.00 L of water is 2.64. Determine the pH of the solution after adding 0.079 moles of sodium hydroxide (NaOH). The Ka for acetic acid is 1.75E-5 (Assume the final volume is 1.00L)
pKa = -log Ka
pKa = -log (1.7 x 10^-5)
pKa = 4.77
CH3COOH + NaOH ---------------------> CH3COONa + H2O
0.350 0.079 0 0 ----------------> initial
0.271 0.0 0.079 0.079 --------------> after reaction
pH = pKa + log [CH3COONa / CH3COOH]
pH = 4.77 + log (0.079 / 0.271)
pH = 4.24