Question

In: Chemistry

What is the pH of a buffer prepared by mixing 20.00 mL of 0.0300 M ammonium...

What is the pH of a buffer prepared by mixing 20.00 mL of 0.0300 M ammonium chloride with 40.00 mL of 0.0450 M ammonia? What is the resulting pH if 1.00 mL of 0.10 M HCl is added to this solution?

Solutions

Expert Solution

no of moles of NH4Cl   = molarity * volume in L

                                     = 0.03*0.02   = 0.0006moles

no of moles of NH3       = molarity * volume in L

                                      = 0.045*0.04 = 0.0018moles

POH      = PKb + log[NH4Cl]/[NH3]

                = 4.75 + log0.0006/0.0018

               = 4.75-0.4771   = 4.2729

PH        = 14-POH

              = 14-4.2729 = 9.7271

By the addition of HCl

no of moles of HCL = molarity * volume in L

                                  = 0.1*0.001 = 0.0001moles

no of moles of NH4Cl    = 0.0006+0.0001 = 0.0007moles

no of moles of NH3       = 0.0018-0.0001 = 0.0017 moles

POH      = PKb + log[NH4Cl]/[NH3]

              = 4.75 + log0.0007/0.0017

               = 4.75-0.3853   = 4.3647

PH          = 14-4.3647   = 9.6353


Related Solutions

a. What is the pH of the buffer prepared by mixing 250. mL of 0.200 M...
a. What is the pH of the buffer prepared by mixing 250. mL of 0.200 M benzoic acid and 100. mL of 0.250M NaOH? pKa=4.19 b. A buffer containing 1.00 M concentrations of HOAc and NaOAc has a pH of 4.742. (a) What is the pH of the soln’ after 0.0100 mol of HCl has been added to 1.00 L of the buffer? (b) What is the pH of the soln’ after the addition of 0.0100 mol of NaOH? (c)...
What is the pH of a buffer that is prepared by mixing 30.0 mL of 1.0...
What is the pH of a buffer that is prepared by mixing 30.0 mL of 1.0 M HF and 20.0 mL of 2.0 M KF? (Ka for HF 7.2 x 10−4) What is the pH of a solution that contains 0.40 M CH3COOH and 0.30 M CH3COONa at 25°C (Ka=1.8 x 10−5)?
What is the pH of a buffer that is prepared by mixing 30.0 mL of 1.0...
What is the pH of a buffer that is prepared by mixing 30.0 mL of 1.0 M HF and 20.0 mL of 2.0 M KF? (K a a for HF 7.2 x 10 −4 )
a) What is the pH of a buffer solution prepared by mixing 120 mL of a...
a) What is the pH of a buffer solution prepared by mixing 120 mL of a 0.435 M CH3CO2H with 50 mL of a .286 M CH3CO2Na solution? CH3CO2H Ka = 1.75 x 10-5 b) What is the resulting pH if we add 10.2 mL of a .513 M HCl solution to this buffer? Does the pH make sense? Why/why not? c) What is the resulting pH if we add 3.56 mL of a 0.420 M NaOH solution to the...
1. Determine the pH of the buffer solution that is prepared by mixing 259 mL of...
1. Determine the pH of the buffer solution that is prepared by mixing 259 mL of 0.0983 M BIS−TRIS propane−H (C11H27N2O6+ ) to 855 mL of 0.0729 M BIS-TRIS_propane (C11H26N2O6) ). Assume the 5% approximation is valid. Report your answer to 2 decimal places. The pKa of BIS−TRIS propane−H is 9.10. Submit Answer Tries 0/3 2. Determine the pH of the BIS−TRIS propane−H/BIS−TRIS propane buffer solution after the addition of 25.2 mL of 0.643 M solution of rubidium hydroxide to...
Calculate the ph after mixing 100 ml of .075 M ammonium chloride with 76 ml of...
Calculate the ph after mixing 100 ml of .075 M ammonium chloride with 76 ml of .1 M LiOH
Calculate the pH of a buffer solution prepared by mixing 20 mL of 5.0% acetic acid...
Calculate the pH of a buffer solution prepared by mixing 20 mL of 5.0% acetic acid with 20 mL of 0.50 M NaOH and 100 mL of water
A buffer solution was prepared by mixing 300.0 mL of a 0.200 M solution of hydroxylamine...
A buffer solution was prepared by mixing 300.0 mL of a 0.200 M solution of hydroxylamine (OHNH2, Kb = 1.1 × 10-8) and 250.0 mL of a 0.300 M solution of its hydrochloride salt (OHNH3+ Cl- ). Calculate the pH of the solution after the addition of 1.08 g of solid NaOH (molar mass = 40.00 g/mol). Assume that there is no volume change upon the addition of solid.
A buffer solution was prepared by mixing 300.0 mL of a 0.200 M solution of hydroxylamine...
A buffer solution was prepared by mixing 300.0 mL of a 0.200 M solution of hydroxylamine (OHNH2, Kb = 1.1 × 10-8) and 250.0 mL of a 0.300 M solution of its hydrochloride salt (OHNH3+ Cl- ). Calculate the pH of the solution after the addition of 1.08 g of solid NaOH (molar mass = 40.00 g/mol). Assume that there is no volume change upon the addition of solid. A. 8.22    B. 5.55 C. 6.30 D. 5.78
A buffer is prepared by mixing 206 mL of 0.452 M HCl and 0.470 L of...
A buffer is prepared by mixing 206 mL of 0.452 M HCl and 0.470 L of 0.400 M sodium acetate. What is the pH? How many grams of KOH must be added to 0.500 L of the buffer to change the pH by 0.16 units?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT