PKa values and acid-base reactions

Related BrainMass Solutions

• prepare a liter of "carbonate buffer" at a pH of 10.10

  Here it is: pH = pKa + log [A-]/[HA] where A- is the conjugate base (carbonate) and HA is the weak acid (bicarbonate).

• Diprotic acid with ka1 and ka2

  Calculate the two pKa values for the diprotic acid.

• Use Henderson-Hasselbalch to explain how buffers work.

  To answer this one, think about what the H-H equation says (pH = pKa + log [A-]/[HA ]) and what a buffer is (a mixture of significant amounts of both an acid and its conjugate base (or base and its conjugate acid) in equilibrium).

• Understanding buffers and weak acids.

  So, if there were 3 pKa values given, the weak acid would have three ionizable protons.)

• pH calculations for buffers, mixtures of acids and bases

  The chemical equation for the equilibrium between weak acid and weak base would be: HCO3(1-) * H(1+) + CO3(2-) Step 4: Look up the pKa of your weak acid. pKa values can be found in textbooks.

• Plotting a titration curve for Ala and His

  The zwitterion is the dominant species in aqueous solutions around physiological pH ( 7), but it can undergo acid-base reactions if we add either a strong acid or a strong base to the solution.

• Finding the pKa of a weak acid.

  From Henderson-Hasselbalch equation pH = pKa + log ([conjugate base]/[acid]) Here pH = 5.55 NaOH in 150 ml = 0.250 M NaOH in 1000 ml = 0.250*150/1000 = 0.0375 M Similarly HB in 250 ml = 0.350 M HB in

• PH / buffer; required salt acid ratio

  base (salt) and [HA] is the concentration of the weak acid.

• Calculating the pH of a buffer

  base and [HA] is the concentration of the weak acid.