Question

In a solution of a weak acid and its conjugate base, which condition has to be true for pH to equal pKa?

The concentration of acid has to be greater than the concentration of base.

The concentration of acid has to be equal to the concentration of base.

An indicator has to be present that changes color at pKa.

Answer 1

You can reason this out.
pH = pKa + log (base)/(acid)
So if pH = pKa, then log (base)/(acid) must be zero. Set that as an equation to get log (base)/(acid) = 0
and 10^0 = ?
? must be 1; how do you get 1 out of
log(base)/(acid). The only way to obtain 1 is for (base) = (acid) which means log(base)/(acid) = log 1 = 0, then
pH = pKa.

Answer 2

so is it a b or c

Answer 3

for anyone else needing this info it is b