When comparing the reaction rates of powdered sodium bicarbonate (NaHCO₃) to that of a whole Alka-Seltzer tablet (which includes NaHCO₃ as well as acid and other ingredients), the surface area is a significant factor.
In the case of a powdered form of NaHCO₃, it has a much larger surface area exposed to the reacting solution, which allows for more frequent collisions between reactant molecules.
On the other hand, a whole Alka-Seltzer tablet has a smaller surface area exposed to the reacting solution. As a result, the reaction would occur at a slower rate because there are fewer surface interactions between the reactants.
Given this reasoning, the correct answer would be:
b The rate of the reaction would slow down.