What is the method to increase the surface area of a solid reactant?

Grinding a solid reactant into a powder effectively increases its surface area. When a solid is reduced to a powder, each particle is smaller and has a larger surface area relative to its volume. This increased surface area allows for more exposure to other reactants, leading to more frequent collisions and interactions, which can enhance the rate of reaction.

In contrast, heating a solid may change its physical state but does not necessarily increase surface area; it can even lead to the opposite effect if the material melts or sublimates. Mixing with liquids or adding gases might alter the overall reaction conditions but does not inherently change the surface area of the solid in a significant way. Therefore, grinding is the most effective method to increase the surface area of a solid reactant.