Define and explain the order of a reaction. How is it obtained exprimentally ?

Explanation

Order of a reaction : The sum of the concentration terms of the reactants present in the rate equation is called order of a reaction.
`to` Order of a reaction can be `0,1,2,3,` and even a fraction
`{:(Eg: 1 N_(2)O_(5)to N_(2)O_(4)+1/2 O_(2)),(rate prop [N_(2)O_(5)]),(therefore "It is a first order reaction."):}|{:(2 2 N_(2)Oto 2N_(2)+O_(2)),(rate prop [N_(2)O]^(2)),(therefore "It is" 2^(nd) "order reaction"):}`
`to` Order of a reaction can be determined exprimentally
Half- Time `(t_(1//2))` method : The time required for the initial concentration (a) of the rectant to become half its value (a/2) during the progress of the reaction is called half-time `(t_(1//2))` of the reaction.
a general expression for the half life, `(t_(1//2))` is given by
`t_(1//2)prop (1)/(a ^(n-1))`
Therefore, for a given reaction two half time values `(t_(1//2) and t_(1//2))` with initial concentrations a and a" respectively are determined experimentally and the order is estabished from the equation.
`((t'_(1//2))/(t"_(1//2)))=((a)/(a))^(n-1)`
Where 'n' is the order of the reaction.