Difference Between Catalytic and Stoichiometric Reagents

The key difference between catalytic and stoichiometric reagents is that catalytic reagents are not consumed during the reaction, whereas stoichiometric reagents are consumed during the reaction.

Catalytic reagents and stoichiometric reagents are two types of reactants in a particular chemical reaction. Catalytic reagents are superior to stoichiometric reagents. This is because the chemical products of a particular chemical reaction should be designed in such a way that at the end of the reaction, the reactants of the reaction should be broken down into small degradation products that do not persist in the environment.

CONTENTS

1. Overview and Key Difference
2. What are Catalytic Reagents 
3. What are Stoichiometric Reagents 
4. Side by Side Comparison – Catalytic vs Stoichiometric Reagents in Tabular Form
5. Summary

What are Catalytic Reagents?

Catalytic reagents are reactants in particular chemical reactions which are not consumed during the reaction. Catalyst is a substance that can increase the reaction rate of a particular chemical reaction. The process of increasing the reaction rate is “catalysis”. The most specific property of a catalyst is that the chemical reaction does not consume the catalysts during the progression of the reaction. However, this substance directly participates in the reaction. Therefore, this substance recycles, and we can separate it from the reaction mixture in order to use it for another reaction. Moreover, we need only a small amount of the catalyst for the catalysis of a chemical reaction.

Generally, chemical reactions occur faster when there is a catalyst. It is because a catalyst can provide an alternative pathway for the reaction to occur. The alternative pathway always has low activation energy than the usual pathway (which occurs in the absence of catalyst). Moreover, catalyst tends to form an intermediate with the reactant, and it regenerates later. However, if a substance decreases the reaction rate, we call it an inhibitor.

We can classify catalysts as either homogeneous or heterogeneous catalysts. If it is homogeneous, it means that the catalyst and reactants are in the same phase of matter (i.e., liquid phase). On the other hand, if the catalyst is in a different phase from that of the reactants, then it is a heterogeneous catalyst. Here, gaseous reactants adsorbed on to a solid catalyst surface.

What are Stoichiometric Reagents?

Stoichiometric reagents are reactants in a chemical reaction that are consumed during the reaction. Therefore, a stoichiometric reagent actively participates in the chemical reaction. Due to this consumption, stoichiometric reagent does not regenerate after the completion of the reaction.

Moreover, this type of reagents is different from catalytic reagents because they do not increase the reaction rate (no effect on the activation energy).

What is the Difference Between Catalytic and Stoichiometric Reagents?

The key difference between catalytic and stoichiometric reagents is that catalytic reagents are not consumed during the reaction, whereas stoichiometric reagents are consumed during the reaction. Therefore, catalytic reagents are superior to stoichiometric reagents. Moreover, catalytic reagents can decrease the activation energy barrier of a chemical reaction, whereas stoichiometric reagents cannot affect the activation energy.

The following table summarizes the difference between catalytic and stoichiometric reagents.

Summary – Catalytic vs Stoichiometric Reagents

Catalytic reagents and stoichiometric reagents are two types of reactants in a particular chemical reaction. The key difference between catalytic and stoichiometric reagents is that catalytic reagents are not consumed during the reaction, whereas stoichiometric reagents are consumed during the reaction. Hence, catalytic reagents are superior to stoichiometric reagents.

Reference:

1. “Stoichiometry.” Wikipedia, Wikimedia Foundation, 18 Feb. 2020, Available here.
2. Helmenstine, Anne Marie. “Reagent Definition and Examples.” ThoughtCo, May. 8, 2019, Available here.

Image Courtesy:

1. “Carbonic anhydrase reaction in tissue” By Fvasconcellos (talk · contribs) – Image: Activation2 updated.svg (CC BY-SA 3.0) via Commons Wikimedia
2. “Gram stain reagents in order water wash btwn each” By Niels Olson  (CC BY-SA 2.0) via Flickr