Question

In: Chemistry

You wish to titrate a 0.193 M solution of HCN (pKa = 9.24) with a 0.183...

You wish to titrate a 0.193 M solution of HCN (pKa = 9.24) with a 0.183 M solution of NaOH. What is the pH of the HCN solution before the titration?

Solutions

Expert Solution

HCN before the titration:

HCN <-> H+ +CN-

Ka= [H+][CN-]/[HCN]

in equilibrium:

[H+] = x

[CN-] = x

[HCN] = M-x = 0.193 - x

so

Ka = 10^-pKA = 10^-9.24 = 5.75*10^-10

so, substitute in Ka expression:

5.75*10^-10= x*x/(0.193-x)

solve for x:

x^2 + Ka*x - M*Ka = 0

x = 1.053*10^-5

[H+] = 1.053*10^-5

pH = -log(1.053*10^-5) = 4.977

approx, before any base is added


Related Solutions

You wish to titrate a 0.164 M solution of HCN (pKa = 9.30) with a 0.161...
You wish to titrate a 0.164 M solution of HCN (pKa = 9.30) with a 0.161 M solution of NaOH. If you start with 44.8 mL of the HCN solution, what is the pH after the addition of 10.1 mL NaOH solution?
You wish to titrate a 0.147 M solution of HCN (pKa = 9.26) with a 0.163...
You wish to titrate a 0.147 M solution of HCN (pKa = 9.26) with a 0.163 M solution of NaOH. Ultimately, you add 117.4 mL of the NaOH solution to the 47.4 mL of HCN solution. What is the pH of the resulting solution?
What is the pH of a 2.62 x 10 -1 M HCN solution? NB the pKa...
What is the pH of a 2.62 x 10 -1 M HCN solution? NB the pKa for HCN = 9.212.
HCN has a pKa = 6.2 x 10-10. If a 50.0 mL of 0.100 M HCN...
HCN has a pKa = 6.2 x 10-10. If a 50.0 mL of 0.100 M HCN is titrated with 0.100 M NaOH, calculate the pH   a) after 8.00 mL base, b) at the halfway point of the titration, c) at the equivalence point. Answers are below, I need to know how to get to them step by step/conceptually Confirm: a) 8.49 , b) 9.21 c) 10.96
A 0.1000 M NaOH solution was employed to titrate a 25.00-mL solution that contains 0.1000 M...
A 0.1000 M NaOH solution was employed to titrate a 25.00-mL solution that contains 0.1000 M HCl and 0.0500 M HOAc. a) Please determine the pH of the solution after 27.00 mL of NaOH is added. Ka, HOAc = 1.75*10-5 b) what's the solution pH at the second equivalence point?
The pH of 0.30 M solution of HCN is 5.20. Calculate the Ka value for HCN.
The pH of 0.30 M solution of HCN is 5.20. Calculate the Ka value for HCN.
A buffer solution that is 0.325 M in HCN and 0.325 M in KCN has a...
A buffer solution that is 0.325 M in HCN and 0.325 M in KCN has a pH of 9.40. Addition of which of the following would increase the capacity of the buffer for added H3O+? both HCN and KCN pure water HCN KCN None of the Above One or more of these choices is the answer, please answer in that format. I have already asked this question and got the wrong answer. A buffer solution is made that is 0.388...
A buffer solution is 0.390 M in HCN and 0.327 M in NaCN. If Ka for...
A buffer solution is 0.390 M in HCN and 0.327 M in NaCN. If Ka for HCN is 4.0×10-10, what is the pH of this buffer solution?
A buffer solution is 0.417 M in HCN and 0.326 M in NaCN . If Ka...
A buffer solution is 0.417 M in HCN and 0.326 M in NaCN . If Ka for HCN is 4.0×10-10, what is the pH of this buffer solution? A buffer solution is 0.418 M in H2SO3 and 0.253 M in NaHSO3. If Ka1 for H2SO3 is , what is the pH of this buffer solution? pH =
A 0.4000 M solution of nitric acid is used to titrate 50.00 mL of 0.237 M...
A 0.4000 M solution of nitric acid is used to titrate 50.00 mL of 0.237 M barium hydroxide. Using this information, complete the following: A.) Write a net ionic equation for the reaction that takes place during titration B.) What species are present at the equivalence point? C.) What volume is nitric acid is required to reach the equivalence point?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT