4. Buffer capacity is defined as the ration of number of moles of acid [H+] or base [OH-] added per 1 liter of the solution to the change in pH of the solutionp.
the effective buffer capacity is from pka-1 to pka+1
and the pKa formic acid , the effective buffer capacity is 2.74 to 4.74( pKa of formic acid is 3.74)
A solution of formic/sodium acetate is expected to act as buffer between the pH range 2.74 to 4.74(
5. The pOH of basic buffer is given pOH = pkb + log(C5H5NHBr/C5H5N)
pKb of C5H5N = -logKb = -log(1.40*10^-9) = 8.85
[C5H5N] = 3.48 M
[C5H5NHBr] = 2.52 M
pOH = 8.85 + log(2.52/3.48)= 8.71
====> pH = 5.29
6.
after addition of NaOH
poH of buffer = pkb + log((C5H5NHBr+HCl)/(C5H5N-HCl))
pOH = 8.85+log((2.205+0.474)/(3.045-0.474) = 8.86
pH = 5.14
4. Briefly explain the meaning of the term buffer capacity". A formic acid/sodium formate solution would...
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