Answer:
Pyruvic acid: conjugate base
Lactic acid: conjugate base
Explanation:
The ratio of conjugate base to conjugate acid can be found using the Henderson-Hasselbalch equation when the pH and pKa are known.
pH = pKa + log([A⁻]/[HA])
The equation can be rearranged to solve for the ratio:
pH - pKa = log([A⁻]/[HA])
[A⁻]/[HA] = 10^(pH-pKa)
Now we can calculate the ratio for the pyruvic acid:
[A⁻]/[HA] = 10^(pH-pKa) = 10^(7.4 - 2.50) = 79433
[A⁻] = 79433[HA]
There is a much higher concentration of the conjugate base.
Similarly for lactic acid:
[A⁻]/[HA] = 10^(pH-pKa) = 10^(7.4 - 3.86) = 3467
[A⁻] = 3467[HA]
For lactic acid the conjugate base also dominates at pH 7.4
From the balanced chemical equation,
4Fe + 3O₂ --> 2Fe₂O₃
it is evident that for every 4 moles of Fe (iron), 2 moles of iron (III) oxide will be formed. Using the same ratio,
8 moles of iron x (2 moles Fe₂O₃ / 4 moles of Fe)
= 4 moles Fe₂O₃
Therefore, the answer is 4 moles.
