Which of the following has the highest buffer capacity?
A. 0.10M H2PO4-/0.10M HPO4 2-
B. 0.50M H2PO4-/0.10M HPO4 2-
C. 0.10M H2PO4-/0.50M HPO4 2-
D. 0.50M H2PO4-/0.50M HPOr 2-
E. They all have the same buffer capacity.
Double checking I believe C is the right answer.
It's D, they are in equal amounts and the greatest concentration.
To compare the buffer capacities, we need to consider the Henderson-Hasselbalch equation, which is given by:
pH = pKa + log ([A-]/[HA]),
where [A-] is the concentration of the conjugate base and [HA] is the concentration of the weak acid.
In this case, the weak acid is H2PO4- and the conjugate base is HPO4 2-.
To determine the buffer capacity, we need to compare the ratios [A-]/[HA] for each option. Let's calculate the ratios for each option:
A. [HPO4 2-]/[H2PO4-] = (0.10)/(0.10) = 1
B. [HPO4 2-]/[H2PO4-] = (0.10)/(0.50) = 0.2
C. [HPO4 2-]/[H2PO4-] = (0.50)/(0.10) = 5
D. [HPO4 2-]/[H2PO4-] = (0.50)/(0.50) = 1
E. The same buffer capacity is not possible unless the concentrations of the acid and its conjugate base are equal.
Comparing the ratios, we see that option C has the highest ratio of [A-]/[HA]. Therefore, the correct answer is C: 0.10M H2PO4-/0.50M HPO4 2-.
To determine which of the given buffer systems has the highest buffer capacity, we need to compare the concentrations of the weak acid (H2PO4-) and its conjugate base (HPO4 2-).
Buffer capacity is the measure of how well a buffer resists a change in pH when an acid or base is added. It depends on the concentrations of the weak acid and its conjugate base. The higher the concentrations of these species in a buffer system, the higher its buffer capacity.
Let's compare the concentrations of H2PO4- and HPO4 2- in each option:
A. 0.10M H2PO4-/0.10M HPO4 2- (Equal concentrations)
B. 0.50M H2PO4-/0.10M HPO4 2- (Higher concentration of H2PO4- compared to HPO4 2-)
C. 0.10M H2PO4-/0.50M HPO4 2- (Higher concentration of HPO4 2- compared to H2PO4-)
D. 0.50M H2PO4-/0.50M HPO4 2- (Equal concentrations)
E. They all have the same buffer capacity.
From the comparison, option C has the highest buffer capacity because it has a higher concentration of the conjugate base (HPO4 2-) compared to the weak acid (H2PO4-).
Therefore, your initial belief that option C is the correct answer is correct.
No. This is not the same post as before. The other one was carbonate/bicarbonate. This is dihydrogen phosphate/monohydrogen phosphate.
C doesn't have the a ratio of 1.0 does it. Nope. Can't be right when there are two others listed that do have a ratio of 1.0. And you pick the one with the highest concn for the highest buffer capacity.