Question

What is the pH of a buffer that consists of 0.15 M CH3CH2COOH and 0.20 M CH3CH2COONa? What is the pH of this buffer after the addition of 5.0 mL of 0.10 M NaOH to 1.0 L of the solution?

Answer 1

- pka of CH3 CH₂ cool=4.87 0.15 cas concentration of CH₂ CH₂ COOH = concentration of CH₂ CH₂ cooNa = 0.2 PH= pka tlog salt] y [Acid PH= 4.87 +10g. CO2) (6) =) PH= 4.995 n 5 if we add 5 ml of 0.10m Nach . moles of NaOH added = 0.0005 . New moles of CH₃COOH = 0.15-0.0005 = 0.1495 New moles of CHz Coo Na = 0.20 +0.0005 = 0.2005 PH= pka + log (Salt] [Acid = 4.87 + log 10-2005) ol0.1495 ) = 4.997 ~ 5