to occur though if it did the pH would be expected to rise above 7. So, it may come a surprise that a solution of KNO3, while almost neutral, a 10% solution exhibits a pH of about 6.2 at 14 °C (57 °F).
The aqueous solution is almost neutral, exhibiting pH 6.2 at 14 °C (57 °F) for a 10% solution of commercial powder (see Potassium nitrate - Wikipedia). A 10% solution is just about 1 M, not 0.1 M so one can estimate that the pH will be between 6.2 and 7. In principle, you should be able to calculate a pKa but, if you do, you’d have to use the equilibrium above but it does not make sense since the right side of the equation gives rise to OH-, not H+.
Further investigation of the wiki page also says the pKb for KNO3 is 15.3. This would suggest that in water, the pH would be 7. Guess you need to carefully read what you read on the internet.
Edit
Toby Block wrote and pointed out that my pH value for the ~1 M solution of KNO3 was obtained at a temp of 14º C. pH is temperature dependent because of its if effect on Kw. At 25º C, the pH of water is 7. As the temperature is lower, the pH rises and at 14º C, the pH of water is about 7.17. So, temperature does not explain why the pH of a 1 M KNO3 solution at 14º C should be less than 7.
to occur though if it did the pH would be expected to rise above 7. So, it may come a surprise that a solution of KNO3, while almost neutral, a 10% solution exhibits a pH of about 6.2 at 14 °C (57 °F).
The aqueous solution is almost neutral, exhibiting pH 6.2 at 14 °C (57 °F) for a 10% solution of commercial powder (see Potassium nitrate - Wikipedia). A 10% solution is just about 1 M, not 0.1 M so one can estimate that the pH will be between 6.2 and 7. In principle, you should be able to calculate a pKa but, if you do, you’d have to use the equilibrium above but it does not make sense since the right side of the equation gives rise to OH-, not H+.
Further investigation of the wiki page also says the pKb for KNO3 is 15.3. This would suggest that in water, the pH would be 7. Guess you need to carefully read what you read on the internet.
Edit
Toby Block wrote and pointed out that my pH value for the ~1 M solution of KNO3 was obtained at a temp of 14º C. pH is temperature dependent because of its if effect on Kw. At 25º C, the pH of water is 7. As the temperature is lower, the pH rises and at 14º C, the pH of water is about 7.17. So, temperature does not explain why the pH of a 1 M KNO3 solution at 14º C should be less than 7.
Neither potassium ion, [math]K^{+}(aq)[/math], nor nitrate ion, [math]NO_{3}^{-}(aq)[/math], cause water hydrolysis. The [math]pH[/math] of an aqueous solution of potassium nitrate at this concentration should be close to [math]7.0[/math].
Neither potassium ion, [math]K^{+}(aq)[/math], nor nitrate ion, [math]NO_{3}^{-}(aq)[/math], cause water hydrolysis. The [math]pH[/math] of an aqueous solution of potassium nitrate at this concentration should be close to [math]7.0[/math].
As User-12647897857346786776, Guy Clentsmith, and Toby Block wrote, you would expect the pH would be 7. NO3- is the anion of a strong acid (pKa < 0) so, you would not expect that
H2O + KNO3 = HNO3 + KOH
to occur though if it did the pH would be expected to rise above 7. So, it may come a surprise that a solution of KNO3, while almost neutral, a 10% solution exhibits a pH of about 6.2 at 14 °C (57 °F).
The aqueous solution is almost neutral, exhibiting pH 6.2 at 14 °C (57 °F) for a 10% solution of commercial powder (see Potassium nitrate - Wikipedia). A 10% solution is just about 1 M, not 0.1 M so one can estimate that the pH will be between 6.2 and 7. In principle, you should be able to calculate a pKa but, if you do, you’d have to use the equilibrium above but it does not make sense since the right side of the equation gives rise to OH-, not H+.
Further investigation of the wiki page also says the pKb for KNO3 is 15.3. This would suggest that in water, the pH would be 7. Guess you need to carefully read what you read on the internet.
Edit
Toby Block wrote and pointed out that my pH value for the ~1 M solution of KNO3 was obtained at a temp of 14º C. pH is temperature dependent because of its if effect on Kw. At 25º C, the pH of water is 7. As the temperature is lower, the pH rises and at 14º C, the pH of water is about 7.17. So, temperature does not explain why the pH of a 1 M KNO3 solution at 14º C should be less than 7.
As User-12647897857346786776, Guy Clentsmith, and Toby Block wrote, you would expect the pH would be 7. NO3- is the anion of a strong acid (pKa < 0) so, you would not expect that
H2O + KNO3 = HNO3 + KOH
to occur though if it did the pH would be expected to rise above 7. So, it may come a surprise that a solution of KNO3, while almost neutral, a 10% solution exhibits a pH of about 6.2 at 14 °C (57 °F).
The aqueous solution is almost neutral, exhibiting pH 6.2 at 14 °C (57 °F) for a 10% solution of commercial powder (see Potassium nitrate - Wikipedia). A 10% solution is just about 1 M, not 0.1 M so one can estimate that the pH will be between 6.2 and 7. In principle, you should be able to calculate a pKa but, if you do, you’d have to use the equilibrium above but it does not make sense since the right side of the equation gives rise to OH-, not H+.
Further investigation of the wiki page also says the pKb for KNO3 is 15.3. This would suggest that in water, the pH would be 7. Guess you need to carefully read what you read on the internet.
Edit
Toby Block wrote and pointed out that my pH value for the ~1 M solution of KNO3 was obtained at a temp of 14º C. pH is temperature dependent because of its if effect on Kw. At 25º C, the pH of water is 7. As the temperature is lower, the pH rises and at 14º C, the pH of water is about 7.17. So, temperature does not explain why the pH of a 1 M KNO3 solution at 14º C should be less than 7.
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Neither potassium ion, [math]K^{+}(aq)[/math], nor nitrate ion, [math]NO_{3}^{-}(aq)[/math], cause water hydrolysis. The [math]pH[/math] of an aqueous solution of potassium nitrate at this concentration should be close to [math]7.0[/math].
Neither potassium ion, [math]K^{+}(aq)[/math], nor nitrate ion, [math]NO_{3}^{-}(aq)[/math], cause water hydrolysis. The [math]pH[/math] of an aqueous solution of potassium nitrate at this concentration should be close to [math]7.0[/math].
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