Warning. This is a long answer because the question has many parts.
A solute will distribute itself between two immiscible liquids according to its solubilities in those liquids.
If one liquid is an organic solvent and the other is water, we can write
(Bottle 1) Shake 40.0 mL of 1.00 mol/L acetic acid with 20 mL of butan-1-ol. Then titrate 10.0 mL samples of each layer with 0.500 mol/L
Note: The numbers below are made-up examples.
Your original solution of
But you used only 10.0 mL of the 40.0 mL water layer.
The water layer must have contained
(i) Volume of NaOH to titrate organic layer
The original acetic acid solution contained 40.0 mmol
After shaking with butan-1-ol, the water layer contained 32.0 mmol
So the organic layer contained
But you titrated only 10.0 mL of the 20.0 mL layer or
The volume of
(ii) Distribution coefficient
The water layer contained 32.0 mmol
(iii) Bottle 2
I leave you to repeat the above calculations for Bottle 2, which contained 20.0 mL of butan-1-ol, 30.0 mL of
- The solvents are immiscible
- The temperature is constant
- The distribution is at its equilibrium value
(v) Which indicator?
You are titrating a weak acid with a strong base, so the pH at the equivalence point will be basic.
Use phenolphthalein (pH 9).
(vi) pH change in aqueous layer?
The concentration of the original HA was 1.00 mol/L.
After shaking with butan-1-ol, the concentration was less than 1.00 mol/L.
The solution was less acidic (more basic), so the pH increased (perhaps from pH 3 to pH 4).