What is the pH of a mixture of equal volumes of 0.1 M glycine and 0.05 M NaOH?

Question

I can't figure out this question. This is the only information given.

Answer 1

Glycine, H₂NCH₂COOH     pka1 = 2.34           pka2=9.60

 

 

 Reaction :   H₂NCH₂COOH  +  NaOH    ------->  H₂NCH₂COO- Na +      +  H₂O

 Initial:          0.1 M                  0.05 M                     0                                               Since the volume is the same  Change:      -0.05 M               -0.05 M                  +0.05 M                                       we can use molarity to determine

 After           0.05 M                    0                         0.05 M                                        change in concentration

 

After reaction you have a mixture of glycine and sodium glycinate (acid and conjugate base), a buffer.

   pH = pka  + log [basic form]/[acidic form]

       = 2.34  + log (0.05M)/(0.05M)

       = 2.34