A finely divided from of a metal burns more readily in air than the rod from because the rod has

A finely divided form of a metal burns more readily in air than the rod form because of its larger surface area. When the surface area of a metal is increased, more of it is exposed to the air, which can lead to increased reactivity. The increased surface area of the finely divided form allows more oxygen molecules to collide with the metal atoms, resulting in a faster and more vigorous reaction. On the other hand, the rod form of a metal has a smaller surface area, making it less reactive as fewer metal atoms are exposed to the air. Therefore, the correct answer is "smaller surface area".