Question

the reaction having order 2 and molecularity 3 represents​

Answer 1

Answer:

A chemical reaction that takes place in one and only one step i.e., all that occurs in a single step is called elementary reaction while a chemical reaction occurring in the sequence of two or more steps is called complicated reaction. The sequence of steps through which a complicated reaction takes place is called reaction – mechanism. Each step in a mechanism is an elementary step reaction.

The molecularity of an elementary reaction is defined as the minimum number of molecules, atoms or ions of the reactants(s) required for the reaction to occur and is equal to the sum of the stoichiometric coefficients of the reactants in the chemical equation of the reaction.

In general, molecularity of simple reactions is equal to the sum of the number of molecules of reactants involved in the balanced stoichiometric equation.

or

The molecularity of a reaction is the number of reactant molecules taking part in a single step of the reaction.

e.g.,

Chemical Reaction

Molecularity

PCl5  →  PCl3 + Cl2  

Unimolecular

2HI  →  H2 + I2

Bimolecular

2SO2 + O2  →  2SO3

Trimolecular

NO + O3  →  NO2 + O2

Bimolecular

2CO + O2  →  2CO2

Trimolecular

2FeCl3 + SnCl2 → SnCl2 + 2FeCl2

Trimolecular

The minimum number of reacting particles (molecules, atoms or ions) that come together or collide in a rate determining step to form product or products is called the molecularity of a reaction.

For example, decomposition of H2O2 takes place in the following two steps:

Decomposition of H2O2.

Overall Reaction

H2O2 → H2O + 1/2O2

Step 1:

H2O2 → H2O + [O]  

Slow

Step 2:

[O] + [O] → O2

Fast

The slowest step is rate-determining. Thus from step 1, reaction appears to be unimolecular.

Step-by-step explanation: