Question

In: Chemistry

Given 100.0 ml of a buffer that is 0.50 M in HOCl and 0.40 M in...

Given 100.0 ml of a buffer that is 0.50 M in HOCl and 0.40 M in NaOCl, what is the pH after 10.0 ml of 1.0 M NaOH has been added?

(Ka for HOCl =3.5 x 10-8)

Solutions

Expert Solution

   Pka = -logka

           = -log3.5*10-8

          =   7.4559

no of moles of HOCl = molarity * volume in L

                                    = 0.5*0.1 = 0.05 moles

no of moles of NaOCl = 0.4*0.1 = 0.04 moles

                          PH   = PKa + log[NaOCl]/[HOCl]

                                  = 7.4559 + log0.04/0.05

                                  = 7.4559-0.0969 = 7.359

By the addition of NaOH

no of moles of NaOH = 1*0.01 = 0.01 moles

no of moles of HOCl   = 0.05-0.01 = 0.04 moles

no of moles of NaOCl   = 0.04+0.01 = 0.05 moles

   PH = Pka + log[NaOCl]/[HOCl]

         = 7.4559 + log0.05/0.04

       = 7.4559 + 0.09691 = 7.5528


Related Solutions

Given that Buffer A contains 200 ml of 0.05 M HOCl and 400 ml 0.03 M...
Given that Buffer A contains 200 ml of 0.05 M HOCl and 400 ml 0.03 M NaOCl, calculate the pH of the buffer solution, the pH of the solution after adding 10 mL of 0.5 M HCl, and the pH of the solution after adding 20 mL of 0.4 M NaOH. Given that Buffer B contains 200 mL 0.5 HOCl and 400 mL 0.3 M NAOCl, calculate the pH of the buffer solution, the pH of the solution after adding...
Consider 500 mL of a buffer comprised of 0.12 M HOCl and 0.080 M KOCl. a)...
Consider 500 mL of a buffer comprised of 0.12 M HOCl and 0.080 M KOCl. a) Do you predict the pH of the buffer to be above or below the pKa? (Please explain) b)Given that HOCl has a Ka= 3.5x108- , Calculate the pH of this buffer? Does your calculated value match your prediction? c)Let's add 2.5 mL of 10 M KOH to this buffer. Do you predict the pH of the buffer to increase, decrease or stay the same...
Calculate the pH of 100.0 mL of a buffer that is 0.0700 M  NH4Cl and 0.115 M...
Calculate the pH of 100.0 mL of a buffer that is 0.0700 M  NH4Cl and 0.115 M NH3 before and after the addition of 1.00 mL of 5.10 M  HNO3. Before= After=
A 100.0 −mL buffer solution is 0.105 M in NH3 and 0.135 M in NH4Br. A....
A 100.0 −mL buffer solution is 0.105 M in NH3 and 0.135 M in NH4Br. A. What mass of HCl could this buffer neutralize before the pH fell below 9.00 B. If the same volume of the buffer were 0.265 M in NH3 and 0.390 M in NH4Br, what mass of HCl could be handled before the pH fell below 9.00? I know for A i have tried .19g, .0915, and .5`3 using three different methods. I have no idea...
A 100.0 −mL buffer solution is 0.110 M in NH3 and 0.125 M in NH4Br. A....
A 100.0 −mL buffer solution is 0.110 M in NH3 and 0.125 M in NH4Br. A. If the same volume of the buffer were 0.260 M in NH3 and 0.395 M in NH4Br, what mass of HCl could be handled before the pH fell below 9.00? B. What mass of HCl could this buffer neutralize before the pH fell below 9.00?
Calculate the pH of 100.0 mL of a buffer that is 0.0850 M NH4Cl and 0.180...
Calculate the pH of 100.0 mL of a buffer that is 0.0850 M NH4Cl and 0.180 M NH3 before and after the addition of 1.00 mL of 5.50 M HNO3. Can you please do a step-by-step of how to solve this, paying special attention to how to get the Ka in the Henderson Hasselbalch Equation? That's the part I'm not understanding.
Calculate the pH of 100.0 mL of a buffer that is 0.0650 M NH4Cl and 0.185...
Calculate the pH of 100.0 mL of a buffer that is 0.0650 M NH4Cl and 0.185 M NH3 before and after the addition of 1.00 mL of 5.90 M HNO3.
Calculate the pH of 100.0 mL of a buffer that is 0.0550 M NH4Cl and 0.180...
Calculate the pH of 100.0 mL of a buffer that is 0.0550 M NH4Cl and 0.180 M NH3 before and after the addition of 1.00 mL of 5.80 M HNO3.
Calculate the pH of 100.0 mL of a buffer that is 0.060 M NH4Cl and 0.185...
Calculate the pH of 100.0 mL of a buffer that is 0.060 M NH4Cl and 0.185 M NH3 after the addition of 1.00 mL of 5.00 M HNO3.
Calculate the pH of 100.0 mL of a buffer that is 0.050 M NH4Cl and 0.180...
Calculate the pH of 100.0 mL of a buffer that is 0.050 M NH4Cl and 0.180 M NH3 before and after the addition of 1.00 mL of 5.70 M HNO3. Before = After=
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT