Explain the terms :
(i) Rate determining step of a reaction,
(ii) Molecularity of a reaction.

Explanation

(i) Rate determining step of a reaction (RDS) : The slowest step of the complex reaction is called rate determining step. E.g.,
Thermal decomposition of nitrous oxide
Step I : `N_(2)O overset("Slowest step")rarr N_(2) + O`
Step II : `N_(2)O + O overset("Fast step")rarr N_(2) + O_(2)`
Rate `= K[N_(2)O]`
`2N_(2)O rarr 2N_(2) + O_(2)`
(ii) Molecularity of reaction : It is the number of reacting species undergoing simultaneous collision in the reaction.
it is a theoretical concept.
it can not be zero.
It does not change with change in temperature and pressure.