Asked by Lorenzo
TRUE OR FALSE?
1) A solution that is made out of 1.00mol/L ammonia and 0.50mol/L of ammonium chloride is a basic buffer.
2) The pH at the equivalence point of a weak base with a strong acid is expected to be less than 7 because the acid that is added is very strong
3) The pH of a buffer solution made out of 0.20mol/L hydrofluoric acid and 0.30mol/L sodiumfluoride is the same as a buffer solution that is made out of 0.10mol/L of acetic acid and 0.15mol/L of sodium acetate.
4) One cannot prepare a buffer from a strong acid and its conjugated base, because a conjugated base of a strong acid cannot buffer; meaning cannot react in the reverse direction of the acid dissociation.
5) The pH at the equivalence point of a weak base with a strong acid is expected to be less than 7 because of the presentce of the conjugated acid in the water.
6) You cannot prepare a buffer from nitric acid and sodium nitrate, but you can make one from nitrous acid and potassium nitrite
7) A solution that is made out of 1.00mol/L ammonia and 0.05mol/L of ammonium chloide can act as a basic buffer.
8) You cannot prepare a buffer with a pH of 11.5 with trimethylamine and trimethylammonium chloride
9) The capacity of a buffer solution made out of 0.20mol/L hydrofluoric acid and 0.30mol/L sodiumfluoride is the higher than that of a buffer solution made out of 0.10mol/L of hydrofluoric acid and 0.15mol/L of sodiumfluoride. But the pH of the two buffers solutions is the same.
I thought it was: true, false, false, true, true true, true, false, false, but it was not the good answer. I've been stuck on this for a looong time, help please!
1) A solution that is made out of 1.00mol/L ammonia and 0.50mol/L of ammonium chloride is a basic buffer.
2) The pH at the equivalence point of a weak base with a strong acid is expected to be less than 7 because the acid that is added is very strong
3) The pH of a buffer solution made out of 0.20mol/L hydrofluoric acid and 0.30mol/L sodiumfluoride is the same as a buffer solution that is made out of 0.10mol/L of acetic acid and 0.15mol/L of sodium acetate.
4) One cannot prepare a buffer from a strong acid and its conjugated base, because a conjugated base of a strong acid cannot buffer; meaning cannot react in the reverse direction of the acid dissociation.
5) The pH at the equivalence point of a weak base with a strong acid is expected to be less than 7 because of the presentce of the conjugated acid in the water.
6) You cannot prepare a buffer from nitric acid and sodium nitrate, but you can make one from nitrous acid and potassium nitrite
7) A solution that is made out of 1.00mol/L ammonia and 0.05mol/L of ammonium chloide can act as a basic buffer.
8) You cannot prepare a buffer with a pH of 11.5 with trimethylamine and trimethylammonium chloride
9) The capacity of a buffer solution made out of 0.20mol/L hydrofluoric acid and 0.30mol/L sodiumfluoride is the higher than that of a buffer solution made out of 0.10mol/L of hydrofluoric acid and 0.15mol/L of sodiumfluoride. But the pH of the two buffers solutions is the same.
I thought it was: true, false, false, true, true true, true, false, false, but it was not the good answer. I've been stuck on this for a looong time, help please!
Answers
Answered by
DrBob222
1) A solution that is made out of 1.00mol/L ammonia and 0.50mol/L of ammonium chloride is a basic buffer.
pH = pKa + log(base/acid)
pH = 9.25 + log(1.00/0.5)
pH = 9.55
basic.
pH = pKa + log(base/acid)
pH = 9.25 + log(1.00/0.5)
pH = 9.55
basic.
Answered by
DrBob222
2) The pH at the equivalence point of a weak base with a strong acid is expected to be less than 7 because the acid that is added is very strong
WB/SA = say NH4Cl. That will be acidic because the NH4^+ is hydrolyzed to produce H3O^+
NH4^+ + H2O ==> H3O^+ + NH3
It is acidic but and I even agree to some extent with the strong acid part but I would count it false because I think they want the answer of the hydrolysis of NH4^+.
WB/SA = say NH4Cl. That will be acidic because the NH4^+ is hydrolyzed to produce H3O^+
NH4^+ + H2O ==> H3O^+ + NH3
It is acidic but and I even agree to some extent with the strong acid part but I would count it false because I think they want the answer of the hydrolysis of NH4^+.
Answered by
DrBob222
3) The pH of a buffer solution made out of 0.20mol/L hydrofluoric acid and 0.30mol/L sodiumfluoride is the same as a buffer solution that is made out of 0.10mol/L of acetic acid and 0.15mol/L of sodium acetate.
HF:
pH = 3.14 + log(0.3/0.2) = 3.33
HAc:
pH = 4.75 + log(0.15/0.1) = 4.93
false
HF:
pH = 3.14 + log(0.3/0.2) = 3.33
HAc:
pH = 4.75 + log(0.15/0.1) = 4.93
false
Answered by
DrBob222
I don't know why the conjugate base can't react (for example Cl^- can react with Ag^+ to form AgCl);however I would go the statement as true.
Answered by
DrBob222
Your other answers look ok to me also; I suspect the outlier may be those where part of the statement is true and part is not true and we must make a guess as to which is right. Sorry I'm not of more help.
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.