Question

relative no of molecules in H2 + cl2=2HCl ​

Answer 1

Answer:

Order of a reaction: Order of a reaction is sum of the powers to which the concentration (pressure) terms are raised in the rate- law expression.

Molecularity of a reaction: It is defined as the number of molecules involved in the step leading to the chemical reaction.

Given reaction is:-

H  

2

​  

+Cl  

2

​  

 

hv

​  

2HCl

& Rate=K

Since the rate of the reaction is independent of the concentration of reactants, so it is a zero order reaction.

Now, No. of molecules involved in the reaction is=2

(One molecule of each of the reactants i.e. H  

2

​  

 & Cl  

2

​  

)

So, as per definition,

Molecularity of the reaction is 2.

Now, [∵] Rate=K (given)