PartB Distribution of coefficent in immiscible solvents

[Fairway]

Homework Statement

Hey guys, I have lab result here for Distribution of coefficient for the solid between water and metylene chloride


Benzoic Acid: 5mg (Weight of solute in methylene chloride)
45mg (Weight of the solute in water )

Succinic Acid: 1mg (Weight of solute in methylene chloride)
49mg (Weight of the solute in water)

Sodium Benzoate: none ( Weight of solute in methylene )
50mg (Weight of the solute in water)

Homework Equations

Becaue the volume of methylene chloride and water (2mL each) are the same in my lab,
K (distribution of coefficient)
= (the weight of the solute in methylene chloride)/ (the weight of solute in water)

The Attempt at a Solution

Benzoic Acid: K=5/45=0.11
Succinic Acid: K=1/49=0.02
Sodium Benzoate: K=0/50=0

Well, I just did what the equation say that but I'm not so sure why the values of K are so small number campare to caffeine K is 4.6 between methylene chloride and water. Thank you so much in advance.

 

[Borek]

Is methylene chloride polar enough to dissolve ionic substance?

 

[Fairway]

if you are referring to sodium benzoate, it dissoloves in water completely becaue of the inonic bond, I think.

 

[Borek]

Will it dissolve in methylene chloride?

What about acids?

 

[Fairway]

I don't think sodium benzoate dissolves in methylene chloride becaue methylene chloride is organic compound and non polar. Other acids such as benzoic acid and succinic acid dissolves mostly in Water because they are di-polar but still dissolves tiny amount in methyle chloride.

 

[Borek]

Not bad. Perhaps you don't have a full picture yet, but you are definitely on the right track.

Benzoic acid is weak, or strong? What happens when it dissociates? What about solubility of charged and uncharged forms in both solvents?

What about caffeine?