I messed up on my titration: filled part of the burette with a supersaturated solution of KHTar(2.073g...MM=188.18amu) dissolved in 150mL diH2O, instead of the 0.051M NaOH solution.
I know it wasn't more than a few mL, but I noticed a huge difference in the volume of NaOH needed for the second aliquot.
Is there anyway to determine mathematically the volume of NaOH I should have used? (I need the correct volume to determine the [HTar-] in solution).
Dissociation:
KHTar(aq)--> K+(aq)+HTar-(aq)
HTar-(aq)+OH-(aq)-->Tar^2-(aq)+H2O(l)
Ksp=[K+][HTar-]--> [K+]=[HTar-]
[HTar-]=[NaOH]x Volume(NaOH)added x (1/Volume KHTar solution)
Volume diH20= 150mL
Amount KHTar= 2.073g
Volume of saturated KHTar sol=25.0mL
[NaOH]=0.051M
Need:
Volume NaOH at neutralization and
[HTar-]
You apparently know the concn of the KHTar but as I read the problem you don't know EXACTLY how much of the tartrate you used in the titration. No, there is no way you can reconstruct the data.
To determine the volume of NaOH that you should have used, we need to equate the moles of HTar-(aq) with the moles of NaOH used for neutralization.
First, let's calculate the number of moles of KHTar that you used:
Molar mass of KHTar = 188.18 g/mol
Mass of KHTar used = 2.073 g
Number of moles of KHTar = Mass / Molar mass = 2.073 g / 188.18 g/mol
Next, let's determine the volume of KHTar solution using the concentration and volume of the saturated solution:
Concentration of KHTar = Number of moles / Volume = (2.073 g / 188.18 g/mol) / 0.025 L
Now, since the stoichiometric ratio between NaOH and HTar- is 1:1, the moles of NaOH used must be equal to the moles of HTar-. Therefore, we can set up an equation:
Number of moles of NaOH = Number of moles of HTar-
Volume of NaOH * Concentration of NaOH = (2.073 g / 188.18 g/mol) / 0.025 L
Rearranging the equation to solve for the volume of NaOH, we have:
Volume of NaOH = [(2.073 g / 188.18 g/mol) / 0.025 L] / Concentration of NaOH
Plug in the values:
Volume of NaOH = [(2.073 g / 188.18 g/mol) / 0.025 L] / 0.051 mol/L
Calculate this value to find the volume of NaOH that you should have used for neutralization.
As for determining [HTar-], you will need the volume of NaOH that you actually used for the titration. Plug that value into the equation you provided:
[HTar-] = [NaOH] * Volume(NaOH added) * (1 / Volume of KHTar solution)
Substitute the known values into the equation to calculate [HTar-].