Final answer:
The anions I-, Br-, Cl-, F-, and OH- are ranked in order of increasing basicity based on the strengths of their conjugate acids and the electronegativity of the atoms involved, with the most basic being OH- and the least basic being I-.
Step-by-step explanation:
The ranking of the anions according to increasing basicity is as follows: I- < Br- < Cl- < F- < OH-. This order is determined by the acid strength of their conjugate acids (HI < HBr < HCl < HF) and the electronegativity of the atoms involved. The stronger the acid, the weaker the conjugate base, and the more electronegative the atom, the less basic the anion is. Hydroxide (OH-) is the most basic because water (H2O) is the weakest acid among the given conjugate acids. On the other end, iodide (I-) is the least basic because HI is the strongest acid of the respective conjugate acids.