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an aqueous buffer solution contains 0.018mol/L NaHCO3 and 0.024mol/L Na2CO3. A)d

ID: 476959 • Letter: A

Question

an aqueous buffer solution contains 0.018mol/L NaHCO3 and 0.024mol/L Na2CO3. A)determine the pH of the solution using Henderson hasselbach. B)determine pH of solution after 1.00mL of 6.00M HCl is added to 499.0 mL of the buffer solution. Assume final volume is 500.0mL. an aqueous buffer solution contains 0.018mol/L NaHCO3 and 0.024mol/L Na2CO3. A)determine the pH of the solution using Henderson hasselbach. B)determine pH of solution after 1.00mL of 6.00M HCl is added to 499.0 mL of the buffer solution. Assume final volume is 500.0mL. an aqueous buffer solution contains 0.018mol/L NaHCO3 and 0.024mol/L Na2CO3. A)determine the pH of the solution using Henderson hasselbach. B)determine pH of solution after 1.00mL of 6.00M HCl is added to 499.0 mL of the buffer solution. Assume final volume is 500.0mL.

Explanation / Answer

A] NaHCO3 ------> Na2CO3

pH = pka + log [NaHCO3] / [Na2CO3]

pH = 10.3 + log [0.024/0.018]

pH = 10.425

B]

NaHCO3 --------> Na2CO3

On addtion of HCl

Moles of NaHCO3 = Molarity*V = 0.018*499 = 8.982 millimoles

Moles of Na2CO3 = 0.024*499 = 11.976 millimoles

Moles of HCl = 6 millimoles

NaHCO3 -------> Na2CO3 + H+

Equilibrium shifts to left forming more NaHCO3

8.982 11.976 6

8.982+6 11.976-6 0

pH = 10.3 + log [11.976-6] / [8.982+6]

pH = 9.9