In: Chemistry
Calculate the pH values of the following solutions (you must show the procedure of calculations:
a-mole of formic acid and 0.02 mole of NaOH diluted to 1L. (formic acid pK=3.75).
b-An aspartic acid solution if the alpha carboxyl is 1/2 dissociated. (aspartic acid pK1= 2.0, pK2=9.9, pKside=3.9)
a)
moles of formic acid = 1
moles of NaOH = 0.02
HCOOH + NaOH -----------------> HCOONa + H2O
1 0.02 0 0
0.98 0 0.02 0.02
here salt and acid remained. so it forms acidic buffer.
pH = pKa + log [salt / acid]
= 3.75 + log [0.02 / 0.98]
= 2.06
pH = 2.06
b)
At 1/2 dissociation pH = pKa1
pH = 2.0