Analyzing Catalyst Form and Reaction Rate

This question concerns the relationship between the physical form of a catalyst, its surface area, and the rate of catalytic hydrogenation.

Statement I Analysis: Catalyst Form and Hydrogenation Rate

Statement I claims that the rate of catalytic hydrogenation is maximal when the catalyst is in a powdered form. This is generally true in heterogeneous catalysis. A larger surface area provides more sites for reactant molecules to adsorb and react, thus increasing the reaction rate.

Statement II Analysis: Powdered Form and Surface Area

Statement II states that a catalyst in powdered form possesses the highest surface area. Reducing the particle size of a solid substance, such as by powdering it, significantly increases its total surface area exposed to the surrounding medium. This principle is fundamental to increasing reaction rates in heterogeneous catalysis.

Linking the Statements

Statement II provides the direct reason for the phenomenon described in Statement I. The powdered form maximizes the catalyst's surface area (Statement II), which in turn leads to the highest rate of catalytic hydrogenation (Statement I) because more active sites are available for the reaction.

Conclusion

Both statements are factually correct. Furthermore, Statement II directly explains why Statement I is true. Therefore, Statement II is the correct explanation for Statement I.