Question

A buffer solution is made using a weak acid, HA , that has a pa of 5 . If the pH of the buffer is 8 , what is the ratio of [A−] to [HA] ?

Answer 1

[A-] : [HA] = 1000 : 1

Step-by-step explanation:

I'm assuming that you mean a pKa of 5 not a pa of 5
For this question, the equation:
pH = pKa + log([A-]/[HA])
plug in pH and pKa
8 = 5 + log([A-]/[HA])
move the 5 from the right to the left
3=log([A-]/[HA])
raise 10 to both sides of the equation to get rid of the log
10^3=10^(log([A-]/[HA]))
1000=[A-]/[HA]
so the ratio of [A-] to [HA] is 1000 to 1