A student must make a buffer solution with a pH of 2.5. Determine which of the a
ID: 960419 • Letter: A
Question
A student must make a buffer solution with a pH of 2.5. Determine which of the acids and conjugate bases listed below are the best options to make a buffer at the specified pH.
The final volume of buffer solution must be 100.00 mL and the final concentration of the weak acid must be 0.100 M. Based on this information, what mass of solid conjugate base should the student weigh out to make the buffer solution with a pH=2.5?
A student must make a buffer solution with a pH of 2.5. Determine which of the acids and conjugate bases listed below are the best options to make a buffer at the specified pH. Weak acids: sodium disulfate monohydrate, K.-1.20x10-2 O phosphoric acid, Ka-7.52x103 O acetic acid, Ka-1.75x105 formic acid, Ka= 1.77x10-4 Conjugate bases: sodium dihydrogen phosphate monohydrate O sodium sulfate decahydrate Na2SO4* 10H20 O sodium acetate trihydrate CH3COONa 3H2O sodium formate HCOONa Scroll down to view more. The final volume of buffer solution must be 100.00 mL and the final concentration of the weak acid must be 0.100 M. Based on this information, what mass of solid conjugate base should the student weigh out to make the buffer solution with a pH-2.5? Number gramsExplanation / Answer
if pH = 2.5
then
pkA = 2.5 approx
or Ka = 10^-2.5 = 0.0031622 = 3.16*10^-3
the best option is that of phosphoric acid
the conjugate base then must be:
anything containing a phosphoric acid conjugate
NaH2PO4*H2O will be a good option
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.