Hey there!:
a) Cations which are lowest size generally forms adopts more number of water molecules around it. Such kind of Cations forms largest hydrated ions. Among given cations, Li+ is smallest one and (C4H9)4N+ is largest one. So, Li+ ion forms largest hydrated ion.
b) Organic ligands or alkyl chains contained Cations are hydrophobic in nature due to its low polar nature. Among given (C₄H₉)4N⁺ cation is hydrophobic in nature.
c) Size of cation inversely proportional to the hydrated sphere or number of water molecules attached. So, in the given Cations (C₄H₉)4N⁺ is largest cation which attaches fewest water molecules.
d) Charge on the cation makes it more electrostatic maker. But size is inversily proportional to electrostatic property. (C₄H₉)4N⁺ is electrostatic structure breaker.
e) Al⁺³ has highest charge. So it is most electrostatic structure maker.
Hope this helps!
