300ml aq solution of 30g malononitrile extracted w/ether If K = 1.5 what results would be acheived from 3 100ml portions of ether...MORE importantly how do you work the problem..thanks
This is a partition coefficient problem. You need to make sure what K is. IF it is organic layer/aqueous layer, then the following applies.
fn = [1 + Kd*(Vo/Va)]-n.
where fn = fraction solute REMAINING in the water layer after n extractions, Vo = volume organic solvent and Va = volume aqueous layer. Post your work if you get stuck.
what volume? sorry out of school for 30yrs! also 2nd part give soluability of 20/100ml in ether & 13.3g/100ml in water and the experiment is being done with 30g (mw 188.61) in 300ml of water to be extracted wih ether. I don't knwo how to proceed
To determine the results achieved from extracting a 300ml aqueous solution of 30g malononitrile with three 100ml portions of ether, we need to understand the concept of distribution coefficient (K) and the process of liquid-liquid extraction.
The distribution coefficient (K) is a measure of how a solute is distributed between two immiscible phases, in this case, between the aqueous solution and ether. It is defined as the ratio of the solute's concentration in the organic phase (in this case, ether) to its concentration in the aqueous phase.
In this problem, the given K value is 1.5, which means the solute (malononitrile) favors the organic phase (ether) more than the aqueous phase.
To work through this problem, follow these steps:
1. Calculate the concentration of malononitrile in the aqueous solution:
- Given: Mass of malononitrile = 30g, Volume of the aqueous solution = 300ml
- Concentration = mass/volume = 30g/300ml = 0.1g/ml
2. Note that each portion of ether has a volume of 100ml. So, the total volume of ether used is 3 * 100ml = 300ml. This volume matches the volume of the aqueous solution, indicating that each portion of ether will be sufficient to extract the entire malononitrile from the aqueous phase.
3. Assume that every portion of ether is completely saturated with malononitrile after extraction. This assumption is based on the fact that the distribution coefficient K is greater than 1, indicating that the malononitrile prefers to dissolve in ether.
4. Calculate the concentration of malononitrile in each portion of ether:
- Concentration = 0.1g/ml (same as in the aqueous solution)
5. After extraction, the malononitrile will be distributed equally among the three portions of ether. Therefore, each portion will have 0.1g/ml of malononitrile.
In summary, the results achieved from three 100ml portions of ether will be that each portion of ether contains 0.1g/ml of malononitrile.