Show It is called catalysis the chemical process by which the speed of a chemical reaction is increased by adding a substance (simple or compound) that alters reaction times without affecting the nature of the final product and without losing its own mass in the process (which is the case with reagents). The substance that increases the speed of the reaction is called catalyst. Many chemical reactions occur very slowly, so a catalyst needs to be added to increase their speed. There are also substances that slow down chemical reactions and are called inhibitors. Substances that increase the rate of chemical reactions are also often called positive catalysts and those that decrease it (inhibitors), negative catalysts. Examples of positive catalyst
Also read: 20 Examples of Chemical Changes Examples of negative catalyst
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them. (i) Positive catalyst: When a catalyst increases the rate of chemical reaction, it is called positive catalyst. (ii) Negative catalyst: When a catalyst decreases the rate of chemical reaction it is called negative catalyst. Example. Phosphoric acid acts as a negative catalyst to decrease the rate of the decomposition of hydrogen peroxide. Alcohol too acts as a negative catalyst in certain chemical reactions. Concept: Classification of Change: Chemical Changes Is there an error in this question or solution? Uh-Oh! That’s all you get for now. We would love to personalise your learning journey. Sign Up to explore more. Sign Up or Login Skip for now Uh-Oh! That’s all you get for now. We would love to personalise your learning journey. Sign Up to explore more. Sign Up or Login Skip for now
The key difference between positive and negative catalyst is that positive catalysts are substances that are capable of increasing the reaction rate, whereas negative catalysts are substances that are capable of decreasing the reaction rate. A positive catalyst is a substance that can increase the rate of reaction without getting involved or consumed in the reaction process. A negative catalyst, on the other hand, is a substance that can decrease the rate of reaction without getting consumed during the reaction. CONTENTS1. Overview and Key Difference What is a Catalyst?A catalyst is a chemical compound that can increase the rate of a reaction without itself being consumed. This compound can continue to act repeatedly in a chemical reaction. Basically, there are four types of catalysts: homogenous catalysts, heterogeneous catalysts, heterogenized homogenous catalysts, and biocatalysts. We can also categorize them as positive and negative catalysts according to their effect on the rate of the chemical reaction. What is a Positive Catalyst?A positive catalyst can be described as a substance that can increase the rate of reaction without getting involved or consumed in the reaction process. These substances can increase the reaction rate or the reaction speed by lowering the chemical reaction’s activation energy. The decomposition of potassium chlorate in the presence of manganese dioxide catalyst (MnO2) is an example of this type of positive catalyst. Since positive catalysts can increase the reaction rate, they can also increase the yield of a chemical reaction. Increasing the reaction rate causes an increase of product given by the reaction per unit time. What is a Negative Catalyst?A negative catalyst can be described as a substance that can decrease the rate of reaction without getting consumed during the reaction. Sometimes, the chemical reactions can be retarded by the presence of foreign substances that are known as negative catalysts. An example of this type of catalyst is phosphoric acid, which acts as a negative catalyst to reduce the reaction rate of the decomposition of hydrogen peroxide. Moreover, we can say alcohols are also able to work as negative catalysts. Moreover, negative catalysts can decrease the yield of a chemical reaction because they can decrease the reaction rate. Decreasing the reaction rate causes the reduction of the product given by the reaction per unit time. What is the Difference Between Positive and Negative Catalyst?Basically, there are four types of catalysts: homogenous catalysts, heterogeneous catalysts, heterogenized homogenous catalysts, and biocatalysts. However, there can be positive and negative catalysts as well, according to the catalyst’s effect on the rate of reaction. The key difference between positive and negative catalyst is that positive catalysts are substances that are capable of increasing the reaction rate, whereas negative catalysts are substances that are capable of decreasing the reaction rate. A positive catalyst works by lowering the activation energy to speed up the reaction; however, a negative catalyst cannot lower the activation energy, so the reaction rate is decreased. The below infographic presents the differences between positive and negative catalyst in tabular form for side by side comparison. We can categorize catalysts as positive and negative catalysts according to their effect on the rate of chemical reactions. The key difference between positive and negative catalyst is that positive catalysts are substances that are capable of increasing the reaction rate, whereas negative catalysts are substances that are capable of decreasing the reaction rate. Reference:1. “What Are (i) Positive Catalysts and (Ii) Negative Catalysts?” Topper. Image Courtesy:1. “Catalysis- Reaction progress” By Smokefoot – Wikimedia Commons (CC0) via Commons Wikimedia |