Question

1. Which of the following solvents is considered the most polar? Which of the following solvents is considered least polar?
Hexane Acetone 70% hexane–30% acetone
2. Which of the following compounds is considered the most polar?
Chlorophyll-a Chlorophyll-b Carotene
3. When using column chromatography to separate the pigments in spinach, which solvent from Question 1 do you start with? Which solvent do you use next?
4. In no more than TWO sentences, explain why it is necessary to change the solvent composition during your column chromatography experiment.

Answer 1

1. hexane acetone (70:30).Least polarity solvent

.hexane acetone (30:70 )more polar

2) Both the chlorophyll a and b are more polar considered as carotene.(. Chlorophyll b slightly more polar then chlorophyll a)

3)hexane: acetone 70:30 was the best solvent system to use to separate the components in the spinach because the amount of nonpolar solvent continually increased while the polar acetone solvent decreased, meaning that more nonpolar solvent would be needed for carotene and chlorophyll (stationary phase) to move with the mobile phase. The balance between the two is essential in separating the spinach components.

4) during the column chomatography solvent composition is change for the collection of fractions of ( chlorophyll a,chlorophyll b ans carotene)