Exercise on pH

[sottozer0]

Hi guys, I have run in this problem.
Calculate the ph of the solution obtained by mixing 50g of potassium nitrate with 1l of H₂O.
Ka = 7,1 * 10^-4
I don't understand if it is a buffer solution or if ir isn't solvable.
Thank you for the replies.

[ChenBeier]

Where did you get the ka value from? The value is wrong. Potassium nitrate is a salt made by nitric acid and potassium hydroxide. Both are strong chemicals, acid and base. Also pH should be near neutral.
Ka of HNO₃ = 20,89, pKa =-1,32

Normaly pH = 14 - 1/2 * (pkB - lg [c anion])

If the value is right then you would get pH 8,42

[Nanisa12]

Potassium nitrate HNO₃ is a salt derived from a strong acid HNO₃ and a strong base KOH. When such a salt dissolves in water, it does not affect the pH of the solution significantly because neither the cation nor the anion hydrolyzes to form H+ or OH- ions. Therefore, the solution remains neutral, and the pH should be around 7

[ChenBeier]

That is what I said above. Why repetation.