Step-by-step explanation:
The rate of a reaction is defined as the rate of disappearance of reactants in a reaction or the rate of conversion of appearance of products during a reaction.
The rate of a reaction depends on the concentration of the reactants, the temperature of the reaction, the nature of reactants, and the presence or absence of catalysts during the reaction.
The surface of reactants comes into play. Reactants with high surface areas react faster than reactants with fewer surface areas. Hence, powdery reactants react faster than solid reactants.
Answer: C. The powdered magnesium react faster because it has a greater surface area.