Basic-Gyan

Transition state theory is also called as " Activated-Complex Theory " or " Theory Of Absolute Rate Of Reactions " or " Absolute Rate Theory " .  This theory was proposed by Henry Erying in 1935 and further modification is done by Merrideth G. Evans   and Michael Polanyi . This theory is used (or provide) as an alternative of the " Collision Theory and Arrhenius Law ".   Since, it is used as an alternative to the Collision theory or Arrhenius law, this theory provides a greater understanding of the activation energy and thermodynamics properties.  .........." The basic assumption of Transition-State theory is the existence of activated complex in which chemical bonds are partially broken and partially formed "........          Transition State Theory (or TST) tells us that there exists an equilibrium state between the state where all molecules are reactants and the state where all molecules are products, known as the " Transiti...

In this article, we will learn about collision theory of a chemical reaction. History Of Collision Theory   Max Trautz and William Lewis  developed the " Collision Theory " for chemical reactions based on the " Kinetic Theory Of Gases " in 1916-18 (because  the gas phase reactions are easy to understand compared to liquid and solid phases reactions).  Therefore the application of the collision theory is limited to the gas phase reaction only.  Assumption Made In Collision Theory We all have heard about the kinetic theory of gases which generally explains the behavior of gases by assuming that the gas consists of molecules or particles or atoms moving rapidly in all directions. All the assumptions made in the kinetic theory of gases are the basis for understanding the collision theory. Introduction To Collision Theory   In this theory, we generally assume that the molecules of the reactant are " Hard Spheres ". Collision theory states that " For a reac...

Rate law or rate equation which shows a relationship between the rate of reaction, reaction rate constant and the concentration of its reactant molecules. For many reactions (particularly elementary reactions), the rate law or rate equation can be written as a product of temperature and concentration dependent terms; ➩ Rate = Function (T)× Function (Concⁿ) The temperature dependent term for such reactions is nothing but the reaction rate constants. Hence, we can say that the rate of reaction is directly proportional to the reaction rate constant. ➩ Rate Of Reaction ∝ Reaction Rate Constant I t has been observed that " The  rate constant for a reaction gets doubled for every 10°C rise in reaction's temperature " and subsequently the rate of reaction is also changed. In 1889, Savante Arrhenius extended the work of J.H. Van't hoff (gives an equation called van't hoff equation to understand how temperature affects the rate constant) and proposed an equation that tel...

Usually we calculate the half-life of a reaction to find the reaction's order. Let us understand what is the half-life of the reaction. " The time taken for the concentration of a given reactant to reach half of its initial concentration (if A is a reactant then, [A] = 1/2 [A]o) is called as the half-life of a reaction ". Half-life is denoted by 't½' . Half-Life Of Reaction Half-life is a period of reaction is defined as the time during which the concentration of a reactant is reduced to half of its initial concentration. The half-life of a reaction 't½' occurs when (consider 'A' as a reactant molecule) ; ➩ [A] = 1/2 [A]₀  Or  [A]₀/2 Remember that the formula for the half-life of a reaction varies along with changing the order of the reaction. And half-life is usually measured in ' Seconds '.  By determining the half-life as a function of initial concentration, one can find the reaction's order and specific reaction rate.  Now Let...

As we know that the Differential rate equation is directly related to the rate laws, while the Integrated rate equations are obtained by integrating the differential rate equations.  The integrated rate law equation expresses the concentration of the reactant as a function of time. The order and rate constant of the reaction can be found from the integrated rate law equation. The Integrated rate law equation is different for different orders of reactions. Using experimental data, one can find out the value of rate constant " k " and predict the order of reaction.  Now, we calculate the integrated rate equations for zero, first and second order reactions one by one in detail; Integrated and Differential Rate Equations (1)  Integrated  And Differential Rate Equations For Zero Order Reaction A zero order reaction is defined as a reaction in which the order of reaction is equal to one. OR   " A zero order reaction takes place at a constant/fixed rate,...