A 19.18 mL of 0.125 M Oxalic Acid (H2C2O42H2O) is titrated with a Ca (OH)2
solution. The initial volume of Ca(OH)2 was 14.38 and the final volume of
Ca(OH)2 was 28.29 mL when the solution turned very slightly pink. What is the
concentration of Ca (OH)2?
H2Ox + Ca(OH)2 ==> CaOx + 2H2O
moles H2Ox = M x L = ??
moles Ca(OH)2 = same as H2Ox because the equation shows the reaction is 1:1.
Then M Ca(OH)2 = mols/L
You know, of course, to find the volume of Ca(OH)2 that you subtract the final volume from the initial volume.
Why is it H2Ox instead of H2C2O4?
To find the concentration of Ca(OH)2, we need to use the concept of stoichiometry and the equation of the reaction between oxalic acid and calcium hydroxide.
The balanced equation for the reaction is:
H2C2O4 + 2Ca(OH)2 -> Ca(C2O4)2 + 3H2O
From the equation, we can see that 1 mole of oxalic acid (H2C2O42H2O) reacts with 2 moles of Ca(OH)2 to produce 1 mole of calcium oxalate (Ca(C2O4)2) and 3 moles of water (H2O).
First, we need to calculate the number of moles of oxalic acid used in the titration. We have the volume of oxalic acid as 19.18 mL and the molarity as 0.125 M.
Moles of H2C2O4 = volume (in L) x molarity
Moles of H2C2O4 = 19.18 mL x (1 L / 1000 mL) x 0.125 mol/L
Next, we need to find the number of moles of Ca(OH)2 that reacted with the oxalic acid. Since the stoichiometric ratio between H2C2O4 and Ca(OH)2 is 1:2, we multiply the moles of H2C2O4 by 2.
Moles of Ca(OH)2 = moles of H2C2O4 x 2
Now, let's calculate the number of moles of Ca(OH)2.