Sapling Learning Homework Help:
Could you help me solve these 3 questions? Thanks.
1. If you are extracting a substance from water into dichloromethane, which is more effective to do:
(a) one extraction with 600 mL of dichloromethane
(b) two extractions with 300 mL of dichloromethane
(c) three extractions with 100 mL of dichloromethane
(d) six extractions with 50 mL dichloromethane
(e) all extractions provide the same degree of efficiency
2. What is the partition coefficient for a system where 300 mL of hexane (density= 0.659 g/cm3) extracts 99.5% of a solute from 100 mL of water in two extractions?
3. If you wish to extract an aqueous solution of ethylamine, a weak base, (pKa of ethylammonium ion = 10.673) into hexane, is it more effective to adjust the aqueous phase to pH 3, pH 8, or pH 12? Why?
Ans 1 a) one extraction with 600mL of dichloromethane.
One extraction is better and efficient than doing multiple extractions as it reduces the chances of error.
Doing multiple extractions is also time consuming process.