First Order Reaction - Practice Questions & MCQ

The rate of the reaction is proportional to the first power.

The chemical reaction occurs as follows:

R            P

a                 0

a-x             x

We have,

  [differentiate rate law]

Unit of 

We know that the first-order equation is given as follows:

But there are other forms of rate law also available that we use for different purposes. These forms are mentioned below:

• Use to solve numericals:
  
  
  
  
  
  
   
• Exponential form:
  
  
  
  This equation is also known as exponential form.

The half-life of a reaction is the time in which the concentration of a reactant is reduced to one half of its initial concentration. It is represented as t_1/2.
For a zero order reaction, rate constant is given as:


The rate constant at t_1/2 becomes:

It is clear that t_1/2 for a zero order reaction is directly proportional to the initial concentration of the reactants and inversely proportional to the rate constant.
For the first order reaction,

So, the above equation becomes