What volume of 0.123 M NaOH(aq) must be added to 125 mL of 0.197 M H2SO3(aq) to reach the following points?

(a) the first stoichiometric point
(b) the second stoichiometric point

2nd.

H2SO3 + 2NaOH ==> Na2SO3 + 2H2O
mols H2SO3 = M x L = ?
mols NaOH = 2 times mols H2SO3
It takes that many mols NaOH to neutralize BOTH H ions of H2SO3.
Then mols NaOH = M x L; you know mols NasOH and M, solve for L NaOH.

Take half that volume to find L for the first stoichiometric point.

moles of H2SO3 = 0.0246

moles of 2NaOH = 0.04925

Second stiochiometric point volume: 400. mL
First stiochiometric point volume: 200. mL

Thanks!

To determine the volume of NaOH(aq) required to reach the first and second stoichiometric points, we need to understand the stoichiometry of the reaction between NaOH and H2SO3. The balanced chemical equation for this reaction is:

2 NaOH(aq) + H2SO3(aq) -> Na2SO3(aq) + 2 H2O(l)

(a) First Stoichiometric Point:
At the first stoichiometric point, the reactants (NaOH and H2SO3) are present in equimolar ratios. This means that the number of moles of NaOH is equal to the number of moles of H2SO3.

To find the volume of NaOH(aq) required to reach the first stoichiometric point, follow these steps:

1. Calculate the number of moles of H2SO3 in 125 mL of 0.197 M H2SO3(aq):
moles of H2SO3 = volume (L) x concentration (M)
moles of H2SO3 = 0.125 L x 0.197 M

2. Use the stoichiometry of the balanced equation to determine the number of moles of NaOH required:
moles of NaOH = moles of H2SO3 / 2

3. Calculate the volume of NaOH(aq) needed, using its concentration:
volume of NaOH(aq) = moles of NaOH / concentration of NaOH

(b) Second Stoichiometric Point:
At the second stoichiometric point, the H2SO3 is completely neutralized and reacts with an additional equivalent of NaOH. This means that for every mole of H2SO3 initially present, after reaching the second stoichiometric point, two moles of NaOH will have been reacted.

To find the volume of NaOH(aq) required to reach the second stoichiometric point, follow these steps:

1. Calculate the number of moles of H2SO3 in 125 mL of 0.197 M H2SO3(aq), as done in step 1 above.

2. Determine the number of moles of NaOH required based on the stoichiometry of the balanced equation. Since two moles of NaOH react with one mole of H2SO3, we need twice the number of moles of NaOH compared to H2SO3 in order to reach the second stoichiometric point.

3. Calculate the volume of NaOH(aq) needed, using its concentration, as done in step 3 above.

By following these steps, you should be able to determine the volume of NaOH(aq) needed to reach both the first and second stoichiometric points.