which of the following has the highest buffer capacity?

A 0.10M H2PO4-/0.10M HPO4 -2
B 0.50 M H2PO4-/0.10 M HPO 2-
C 0.10 M H2PO4-/0.50 M HPO4 2-
D 0.50 M H2PO4-/0.50M HPO4 2-
E They all hae the same buffer capacity.

There is a group of us working together.

To determine which solution has the highest buffer capacity, we need to understand what buffer capacity means and how it is influenced by the concentrations of the weak acid and its conjugate base in the buffer solution.

Buffer capacity refers to the ability of a buffer solution to resist changes in its pH when small amounts of acid or base are added. A buffer solution is generally made up of a weak acid and its conjugate base, or a weak base and its conjugate acid.

The buffer capacity of a solution is highest when the concentrations of the weak acid and its conjugate base are roughly equal, as this allows for efficient neutralization of added acid or base.

Analyzing the given options, let's compare the concentrations of the weak acid and its conjugate base:

A: 0.10 M H2PO4-/0.10 M HPO4 2-
B: 0.50 M H2PO4-/0.10 M HPO 2-
C: 0.10 M H2PO4-/0.50 M HPO4 2-
D: 0.50 M H2PO4-/0.50 M HPO4 2-

Option E suggests that they all have the same buffer capacity, so we'll need to compare the concentrations to determine if that is true.

Looking at the options, we can see that only option A has roughly equal concentrations of the weak acid (H2PO4-) and its conjugate base (HPO4 2-), both being 0.10 M.

Therefore, the correct answer is option A: 0.10 M H2PO4-/0.10 M HPO4 2-. This solution has the highest buffer capacity among the given options.

Then look at the answers I gave to this question earlier. The best buffer for a particular solution is one in which the pKa of the buffer is in the range of the desired pH and when the term, log (base/acid) is 0.