Answer:
Acetic acid 0,055M and acetate 0,095M.
Explanation:
It is possible to prepare a 0,15M buffer of acetic acid/acetate at pH 5,0 using Henderson-Hasselblach formula, thus:
pH = pka + log₁₀ [A⁻]/[HA] <em>-Where A⁻ is acetate ion and HA is acetic acid-</em>
Replacing:
5,0 = 4,76 + log₁₀ [A⁻]/[HA]
<em>1,7378 = [A⁻]/[HA] </em><em>(1)</em>
As concentration of buffer is 0,15M, it is possible to write:
<em>[A⁻] + [HA] = 0,15M </em><em>(2)</em>
Replacing (1) in (2):
1,7378[HA] + [HA] = 0,15M
2,7378[HA] = 0,15M
[HA] = 0,055M
Thus, [A⁻] = 0,095M
That means you need <em>acetic acid 0,055M</em> and <em>acetate 0,095M</em> to obtain the buffer you need.
i hope it helps!
