Which 1-mole sample has the least entropy?

(1) Br2 (s) at 266 K (3) Br2 (l) at 332 K

(2) Br2 (l) at 266 K (4) Br2 (g) at 332 K

The correct answer is option 1. Entropy is the degree of disorderliness in a system. Among the phases, solid has the most ordered structure. Also, at lower temperatures the molecules will have less kinetic energy therefore less motion. Thus, bromine in solid form at 266K has the least entropy.