Question

What is [h3o ] in a solution of 0.25 m ch3co2h and 0.030 m nach3co2?

Answer 1

Hello!

To determine [H₃O⁺], we need to apply the Henderson-Hasselback equation, since this is a case of an acid and its conjugate base:


`pH=pKa+log( ([A^(-)] )/([HA]) )`


`pH=4,76+log( (0,030M)/(0,25M) ) \\ \\ pH=3,84`

Now, we use the definition of pH and clear [H₃O⁺] from there:


`pH=-log[H_3O^(+)]`


`[H_3O^(+)] = 10^(-pH) =10^(-3,84)=0,00014 M`

So, the [H₃O⁺] concentration is 0,00014 M

Have a nice day!