What is the H_3O^+ and the pH of a buffer that consists of 0.24 M HNO_2 and 0.68 M KNO_2? (K_a of HNO_2 = 7.1 x 10^-4)?

1 Answer
anor277
Jan 3, 2018

Well the [buffer equation operates....](https://socratic.org/questions/how-do-buffers-maintain-ph)

Explanation:

...which says that...

pH=pK_a+log_10{[[A^-]]/[[HA]]}

and so here....pH=3.15+log_10((0.68*mol*L^-1)/(0.24*mol*L^-1))=3.15+0.453=3.60

And so.....

[H_3O^+]=10^(-3.60)*mol*L^-1=2.51xx10^-4*mol*L^-1.

Solution pH is raised relative to pK_a given that the concentration of the conjugate base, the nitrite anion, is GREATER than that of the nitrous acid.

What would pH be, should [NO_2^(-)]=[HNO_2]?

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