How would you calculate the pH of the buffer if 1.0mL of 5.0M NaOH is added to 20.0mL of this buffer?
Can someone please explain to me how to do B and C step by step so I could understand it clearly? :)
Say, for example, that you had prepared a buffer in which you mixed 10.30 g of sodium hydrogen phosphate, Na2HPO4, with 100.0 mL of 1.0 M sodium dihydrogen phosphate, NaH2PO4.
A. Calculate the pH of this buffer.
B. Calculate the resulting pH if 1.0 mL of 5.0 M NaOH is added to 20.0 mL of this buffer.
C. Calculate the mL of HCl that would have to be added to this buffer in order to lower the pH by exactly 1.0 unit.
Im not sure if I did A correctly, but...
Ka = 3.6x10^-13
pKa = -log(3.6x10,^-13)
= 12
10.30g Na2HPO4 x (1 mol Na2HPO4/ 141.96g Na2HPO4)
= 0.7256 mol Na2HPO4 (1.0 mol/1 L) x .1L
= .1 mol NaH2PO4
pH = 12 + log(.1 mol NaH2PO4/.07256 mol Na2HPO4)
= 12.14
For B. How exactly would I write the chemical equation and start the ICF table? And definitely need help on C. :(
Thank you soo much in advance.
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