1. What is the pH of a hypoiodous acid/sodium hypoiodite buffer in which the con
ID: 1030915 • Letter: 1
Question
1. What is the pH of a hypoiodous acid/sodium hypoiodite buffer in which the concentration of the weak acid component is 0.129 M and the concentration of the conjugate base is 0.102 M?Ka=2.3E-11.
2. The pH of a hypoiodous acid/sodium hypoiodite buffer in which the concentration of the weak acid component is 0.140 M and the concentration of the conjugate base is 0.070 M is 10.34. Suppose 0.128 g of solid NaOH are added to 100 mL of this buffer solution. What is the pH after the addition? Ka=2.3E-11.
Explanation / Answer
1.
Concentration of Hypoiodous acid= 0.129M
sodium hypoiodite = 0.102M
Ka= 2.3x10^-11
-log(Ka) = -log(2.3x10^-11)
Pka = 10.64
PH= Pka + log[salt]/[acid]
PH= 10.64 + log(0.102/0.129)
PH= 10.54
2)
concentration of Hypoiodous acid = 0.140M
concentration of sodium iodite = 0.070M
volume = 100 ml
number of moles of acid = 0.140Mx0.100L=0.014 moles
number of moles of conjugate base = 0.070M x0.100L = 0.007 moles
mass of NaOH= 0.128 grams
molar mass of NaOH= 40.0 grams/mole
number of moles of NaOH= 0.128/40.0=0.0032 moles
after addition of NaOH
number of moles of acid = 0.014 - 0.0032 =0.0108moles
number of moles of conjugate base = 0.007 + 0.0032 =0.0102 moles
Ka= 2.3x10^-11
PKa = 10.64
PH= 10.64 + log(0.0102/0.0108)
PH=10.61.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.