A finely divided form of a metal burns more readily in air than the rod form because the rod has
- higher molar mass
-
smaller surface area
- protective oxide coating
- diferent chemical properties
The correct answer is: B
Explanation
The metallic rod has a small surface area relative to the same mass of finely grounded metal. This means that more particles of the finely grounded metal will be in contact with air than the metallic rod. As a result, there can be more successful collisions per unit time and the reaction of finely grounded metal is faster.
Increasing the surface area of the reactants increases the rate of the reaction. Thus, option B is the correct answer.