Which one of the following reactions is an example of heterogeneous catalysis: (a) \(2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{NO}(\mathrm{g})}{\longrightarrow} 2 \mathrm{CO}_{2}\) (b) \(2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{NO}(\mathrm{g})}{\longrightarrow}-2 \mathrm{SO}_{3}\) (c) \(2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{Pt}(\mathrm{s})}{\rightarrow} 2 \mathrm{CO}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CHO}(\mathrm{g}) \stackrel{\mathrm{I}_{2}(\mathrm{~g})}{\longrightarrow} \mathrm{CH}_{4}+\mathrm{CO}\)

In the world of chemistry, a catalyst is a substance that speeds up a chemical reaction without being consumed in the process. When we examine catalysts, one important aspect to understand is their phase, which can be solid, liquid, or gas.

Heterogeneous catalysis is a type of catalysis where the catalyst is in a different phase than the reactants. To clarify, if the reactants are in a gas or liquid phase, the catalyst in a heterogeneous reaction would be a solid (or sometimes a liquid if all reactants are gases). An excellent illustration of this concept is found in the reaction where platinum (Pt), a solid, catalyzes the reaction between carbon monoxide (CO) and oxygen (O2), both gases, to form carbon dioxide (CO2).

Understanding these phases is crucial as it influences how the reactants interact with the catalyst. In heterogeneous catalysis, the reactants adsorb onto the surface of the solid catalyst, where the reaction takes place, before desorbing back into the gas or liquid phase. This physical process of adsorption and desorption is at the core of how heterogeneous catalysts work.

A chemical reaction is a process in which one or more substances, the reactants, are converted into one or more different substances, the products. Reactions can vary widely in terms of speed, mechanisms, and conditions required to initiate and sustain them.

In our exercise, we're analyzing different types of chemical reactions to identify which involve heterogeneous catalysis. In simple terms, a reaction needs a little 'push' to get started, and this is where catalysts come in. They lower the energy barrier for the reaction, which increases the reaction rate without being consumed.

It's important for students, especially those preparing for competitive exams like NEET Chemistry, to grasp the nuances of reactions, such as recognizing the phases of reactants and catalysts, understanding the role catalysts play, and how changing conditions can affect the reaction rate and yield. The heterogeneous catalyst not only increases the rate but can also influence the selectivity of the reaction, leading to more of the desired product. The diverse nature of chemical reactions makes them a fascinating and fundamental topic in chemistry education.

NEET, the National Eligibility cum Entrance Test, is an essential pre-medical examination in India that includes a comprehensive chemistry section. NEET Chemistry covers a wide array of topics, including physical, organic, and inorganic chemistry.

One of the key concepts that frequently appear in NEET is catalysis. Understanding heterogeneous and homogeneous catalysis is important for NEET aspirants because it's not just about identifying the type of catalysis but also understanding the underlying principles and their applications in various chemical processes and industries.

Additionally, NEET aspirants should be well-versed in practical applications, such as how catalysts are used in industrial processes, pollution control, and energy production. Equally, they must be proficient in analyzing different types of reactions, their mechanisms, and predicting the outcomes, skills that are pivotal in both the exam and their future medical studies. Effective preparation for NEET Chemistry requires a thorough comprehension of these concepts, combined with practice problems that test both theoretical knowledge and practical problem-solving skills.