Le Chateliers Principle

[CrazCo]

I did a lab on it using the equation:

 

Co(H20)6^2+ + 4Cl- <=> CoCl4^2- + 6H2O

pink^ blue^

 

When acetone was added to the H2O it consumed some H2O so i expected it to shift right to add more H2O and fix the equilibrium thus turning blue! but only half turned blue (top half, the bottom remained pink) Why?

 

I really don't know where to start except to say acetone is less dense.

[Psycho]

The main idea is to look into whether the two solvents are miscible and then think about why it might have occurred from that stand point.

 

The idea of density is along the right lines.

[CrazCo]

Does the larger density (water) push the smaller density upward and stay at the bottom? This acetone at the top would cause the equation to shift right to add H2O to make up for the ones that were consumed and cause it to be blue, but remain pink on the bottom because it was pink to start with?

[hermanntrude]

acetone and water are miscible (they do mix). However I guess it's possible you put it in quite gently and without stirring, in which case one might float on top of the other.

[John Cuthber]

Acetone does not mix with strong solutions of NaCl or MgSO4. I don't know about CoCl2 solution, because I have not tried it, but I would not expect them to mix.

If there are two layers- one with a lot of water and one with a lot of acetone the experimental observations (a blue layer floating on a pink one) make sense.

[hermanntrude]

i didn't think of that. Nice explanation

[John Cuthber]

I'm not actually sure I explained anything, but I'd like to think I helped.