Answer:
A. CH3CH2CH2CH2CH3
Explanation:
The silica in the plate is polar and contains hydroxil groups in its surface.
Compound B, C, are polar containing hydroxyl gropus and compound D is a carboxylic acid which is polar. It follows then that these compounds will be retained more strongly than the non polar hydrocarbon compound CH3CH2CH2CH2CH3.
Since the retention factor, Rf, is defined as the distance travelled by the solute divided by the distance travelled by the solvent, we can deduce that compound A. CH3CH2CH2CH2CH3 will travel farthest and have the highest Rf.
