posted by Jonah on .
Which of the following pairs would make a good buffer solution in an aqueous solution?
A) H2SO4 and NaHSO4
B) Ca(NO3)2 and HNO3
C) HCl and NaCl
D) HF and NaOH
E) none of them
I know the answer is D but I don't understand why. I would think it would be C since a goo buffer is a weak acid and it's salt.
You are right. D is the correct answer. You are also correct that a good buffer is a weak acid or weak base and its conjugate base/acid. However, HCl is not a weak acid; therefore, it along with sodium chloride is not a good buffer. D is a good buffer because it is a weak acid and its salt. A is not a good buffer because sulfuric acid is not a weak acid. B is not a good buffer because nitric acid is not a weak acid. C is not a good buffer for reasons already outlined.