Answer:Iodide has weaker ion-dipole interactions with water than bromide.
Explanation:
The electronegativity difference between sodium and iodine in sodium iodide is about 1.73. This shows that the compound is not composed of purely ionic bonds. Electro negativity decreases down the group hence iodine is far less electronegative than bromine and is thus ineffective in forming strong dipole interactions with water hence the higher entropy due to much less association of ions in solution.