How many mls of 1M solution of H2SO4 will react with 40 ml of 1M solution of NaOH
Answers
Answer:
This is somewhat of a trick question. H2SO4 is a polyprotic acid and therefore has two dissociations that can potentially liberate H+:
H2SO4 → H+ + HSO4 Ka is so large that H2SO4 dissociates completely.
HSO4 → H+ + SO4- Ka is 0.012 (somewhat low)
It is generally taught for strong polyprotic acid solutions, like H2SO4, that are greater than or equal to 1 M then you only have to focus on the first dissociation:
H2SO4 → H+ + HSO4
Since H2SO4 completely dissociates to H+ and HSO4 then a 1 M H2SO4 solution will yield 1 M H+. So it will take 2 ml of a 1 M H2SO4 solution to neutralize 2 ml of a 1 M NaOH solution.
However, one could also calculate how much H+ will form from the second dissociation:
HSO4 → H+ + SO4-
1 M 0 M 0 M
-x +x +x
1-x x x
(x * x)/(1-x) = 0.012
Solving the quadratic gives x = [H+] = ~0.1 M
So the total [H+] = 1.1 M. Therefore, you would need ~1.82 ml 1 M H2SO4 to neutralize 2 ml of 1 M NaOH.
Explanation: