Zero Order Reaction: Kinetics and Characteristics
by Yuvi K - December 17, 2023
Zero Order Reaction: Kinetics and Characteristics
Most chemical reactions follow a certain kinetics which are easily described using first and second order reactions. However, in some cases, neither of these two orders describes the kinetics of a reaction accurately. Due to this, the concept of Zero order reactions was introduced, which have some interesting characteristics.
What is a Zero Order Reaction?
A Zero-order reaction (शून्य आदेश प्रतिक्रिया) is a type of chemical reaction that follows first-order kinetics.
The reaction rate is observed to be constant and it is independent of the concentration of the reactants at a given temperature. This implies that the rate of a zero-order reaction is not affected by the concentration of the reactants and is independent of both the order of the reaction and the reactant concentrations. The reaction rate for a zero-order reaction is simply given by the rate constant (k) of the reaction.
Characteristics of Zero Order Reaction
- Rate-Constant:The rate constant for a zero-order reaction is independent of the concentrations of the reactants.
- Order of the reaction: A zero-order reaction is a reaction of first order.
- Reaction Mechanism: The reaction mechanism of a zero-order reaction involves a single, unsymmetrical molecularity.
Examples of Zero-Order Reactions
- The hydrolysis of esters is an example of a zero-order reaction.
- The decomposition of N2O4 is also a zero-order reaction.
- The hydrolysis of acetic acid is another example of a zero-order reaction.
- The oxidation of drugs such as benzaldehyde to benzoic acid is another example of a zero-order reaction.
Advantages of Zero-Order Reactions
- The advantage of a zero-order reaction is that the reaction rate is independent of the concentration of the reactants.
- It also allows for a faster reaction rate as compared to a first-order reaction.
- It is also more reliable to predict the rate of the reaction as the rate-constant remains constant.
Disadvantages of Zero-Order Reactions
- The main disadvantage of a zero-order reaction is that it requires a higher concentration of reactants in order to attain a particular rate.
- The reaction time also tends to be much longer than that of first-order reactions.
Conclusion
Zero-order reactions can be seen in certain chemical reactions, such as the decomposition of N2O4 or the oxidation of certain drugs. A zero-order reaction can be characterized by its constant rate-constant, unsymmetrical reaction mechanism, and first-order rate law. While there are some advantages of zero-order reactions, such as a faster reaction rate and a predictable reaction rate, there are also some drawbacks, such as a higher concentration of reactants needed and longer reaction times.
