Question

In: Chemistry

A buffer solution is 0.390 M in HCN and 0.327 M in NaCN. If Ka for...

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?

Solutions

Expert 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


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