In: Chemistry
A buffer solution is 0.390 M in HCN and 0.327 M in NaCN. If Ka for HCN is 4.0×10-10, what is the pH of this buffer solution?
Ka = 4*10^-10
pKa = - log (Ka)
= - log(4*10^-10)
= 9.398
use:
pH = pKa + log {[conjugate base]/[acid]}
pH = pKa + log {[NaCN]/[HCN]}
= 9.398+ log {0.327/0.390}
= 9.321
Answer: 9.32