Question

If a buffer solution is 0.140 M in a weak base (Kb = 5.3 × 10-5)...

If a buffer solution is 0.140 M in a weak base (Kb = 5.3 × 10-5) and 0.530 M in its conjugate acid, what is the pH?

Science   Chemistry   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

B + H2O <--> BH+ + OH-
Kb = [BH+][OH-]/[B] = 1.0 X 10^-5
Substituting the concentrations of the base and its conjugate acid gives:
1.0 X 10^-5 = (0.410) [OH-] / (0.140)
[OH-] = 3.41 X 10^-6
From this, and the expression for Kw,
[H3O+] = 1.0 X 10^-14 / 3.41 X 10^-6 = 2.9X10^-9
and pH = - log 2.9X10^-9 = 8.53
You can also use Kb to calculate Ka and the pKa, and then use the Henderson-Haselbalch equation:
Ka X Kb = Kw
Ka = 1X10^-14 / 1X10^-5 = 1.0 X 10^-9
pKa = 9.00
Then, pH = pKa + log [base]/[acid]
pH = 9.00 + log 0.14 / 0.41 = 8.53

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
If a buffer solution is 0.160 M in a weak acid (Ka = 3.4 × 10-5)...
If a buffer solution is 0.160 M in a weak acid (Ka = 3.4 × 10-5) and 0.510 M in its conjugate base, what is the pH? If a buffer solution is 0.260 M in a weak base (Kb = 6.9 × 10-5) and 0.550 M in its conjugate acid, what is the pH? Please show work that way it's actually learning and not just giving an answer. Thank you!
1.) If a buffer solution is 0.110 M in a weak base (Kb = 5.7 ×...
1.) If a buffer solution is 0.110 M in a weak base (Kb = 5.7 × 10-5) and 0.590 M in its conjugate acid, what is the pH? 2.) You need to prepare 100.0 mL of a pH=4.00 buffer solution using 0.100 M benzoic acid (pKa = 4.20) and 0.240 M sodium benzoate. How much of each solution should be mixed to prepare this buffer? 3.) Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added...
Calculate the pH of a weak base solution ([B]0 > 100 • Kb Calculate the pH...
Calculate the pH of a weak base solution ([B]0 > 100 • Kb Calculate the pH of a 0.106 M aqueous solution of triethanolamine (C6H15O3N, Kb = 5.8×10-7) and the equilibrium concentrations of the weak base and its conjugate acid.
2) A 350.0 −mL buffer solution is 0.140 M in HFand 0.140 M in NaF. What...
2) A 350.0 −mL buffer solution is 0.140 M in HFand 0.140 M in NaF. What mass of NaOH could this buffer neutralize before the pH rises above 4.00? If the same volume of the buffer was 0.360 M in HF and 0.360 M in NaF, what mass of NaOHcould be handled before the pH rises above 4.00? 3) A 5.65 −g sample of a weak acid with Ka=1.3×10−4 was combined with 5.20 mL of 6.10 M NaOH and the...
If a buffer solution is 0.200 M in a weak base (Kb = 7.9
If a buffer solution is 0.200 M in a weak base (Kb = 7.9
You are given a buffer that contains a weak base whose concentration is 0.600 M and...
You are given a buffer that contains a weak base whose concentration is 0.600 M and its conjugate weak acid whose concentration is 0.260 M. The volume of this solution is 0.375 L. If 0.080 L of an HCl solution with a concentration of 1.10 M is added to this solution, what will the pH of the combined solution be? The pKa of the weak acid is 4.67.
NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts...
NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts as a weak acid. What is the pH of a solution that is 0.059 M in NH4Cl at 25 °C? pH =
1)Design a buffer that has a pH of 10.12 using one of the weak base/conjugate acid...
1)Design a buffer that has a pH of 10.12 using one of the weak base/conjugate acid systems shown below. Weak Base Kb Conjugate Acid Ka pKa CH3NH2 4.2×10-4 CH3NH3+ 2.4×10-11 10.62 C6H15O3N 5.9×10-7 C6H15O3NH+ 1.7×10-8 7.77 C5H5N 1.5×10-9 C5H5NH+ 6.7×10-6 5.17 How many grams of the bromide salt of the conjugate acid must be combined with how many grams of the weak base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams bromide...
A buffer is a mixed solution of a weak acid or base, combined with its conjugate....
A buffer is a mixed solution of a weak acid or base, combined with its conjugate. Note that this can be understood essentially as a common-ion problem: The conjugate is a common ion added to an equilibrium system of a weak acid or base. The addition of the conjugate shifts the equilibrium of the system to relieve the stress of the added concentration of the common ion. In a solution consisting of a weak acid or base, the equilibrium shift...
NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts...
NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts as a weak acid. What is the pH of a solution that is 0.071 M in NH4Cl at 25 °C?
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT