a.) Asp and Lys
Asp will elute first from the column because it has less positively charged functional groups than Lys.
b.) Arg and Met
Met will elute first from the column because it has less positively charged functional groups than Lys.
c.) Glu and Val
Glu will elute first from the column because it has more negativity functional groups than Lys and will be not be much retained by the -SO₃⁻ groups from the ion-exchange coloumn.
d.) Gly and Val
Gly will elute first from the column because Lys have a longer alkyl chain which will be attracted by the strongly hydrophobic backbone for the resin.
e.) Ser and Ala
Ser will be eluted first from the column because Ala alkyl chain will be more attracted by the strongly hydrophobic backbone for the resin. Ser have an -OH group which will decrease the hydrophobicity of the alkyl chain and will not be so much retained on the column.
Cl is highly electronegative and will actually pull away 1 electron from sodium, forming an ionic bond.
It is a scientific hypothesis. A scientific hypothesis must be testable, however there is a significantly more grounded necessity that a testable speculation must meet before it can truly be viewed as logical. This foundation comes essentially from crafted by the rationalist of science Karl Popper, and is called "falsifiability".