Write about elementary and complex reactions.
Write about elementary and complex reactions.
A balanced chemical equation never gives us a true picture of how a reaction takes place.
$(a)$ Elementary reaction : The reactions taking place in one step are called elementary reactions. The order of reaction in elementary is equal to molecularity.
$(b)$ Complex reaction : When a sequence of elementary reactions (called mechanism) gives us the products, the reactions are called complex reactions.
The complex reactions involving more than three molecules in the stoichiometric equation must take place in more than one step.
For complex reaction the order is given by the slowest step and molecularity of the slowest step is same of the order of the overall reaction.
Examples: $(i)$ The oxidation of ethane to $\mathrm{CO}_{2}$ and $\mathrm{H}_{2} \mathrm{O}$ passes through a series of a intermediate steps in which alcohol, aldehyde and acid are formed. $(ii)$ Reverse reactions and side reactions (e.g. nitration of phenol yields o-nitrophenol and $p$-nitrophenol)..
Similar Questions
Determine the order of reaction on the basis of following data for the reaction $A + B \to C$
Exp.
$[A]$
$[B]$
Rate of reaction
$1$
$0.1$
$0.1$
$2 \times {10^{ - 3}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$
$2$
$0.4$
$0.1$
$0.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$
$3$
$0.1$
$0.2$
$1.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$
Determine the order of reaction on the basis of following data for the reaction $A + B \to C$
| Exp. | $[A]$ | $[B]$ | Rate of reaction |
| $1$ | $0.1$ | $0.1$ | $2 \times {10^{ - 3}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$ |
| $2$ | $0.4$ | $0.1$ | $0.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$ |
| $3$ | $0.1$ | $0.2$ | $1.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}\,{\sec ^{ - 1}}$ |
For the reaction, $2N_2O_5 \to 4NO_2 + O_2$ rate and rate constant are $1.02 \times 10^{-4}\, mol\,L^{-1}\,s^{-1}$ and $3.4 \times10^{-5}\,s^{-1}$ respectively. The concentration of $N_2O_5$ in $mol\,L^{-1}$ will be
For the reaction, $2N_2O_5 \to 4NO_2 + O_2$ rate and rate constant are $1.02 \times 10^{-4}\, mol\,L^{-1}\,s^{-1}$ and $3.4 \times10^{-5}\,s^{-1}$ respectively. The concentration of $N_2O_5$ in $mol\,L^{-1}$ will be
Diazonium salt decomposes as ${C_6}{H_5}N_2^ + C{l^ - } \to {C_6}{H_5}Cl + {N_2}$ At ${0\,^o}C$, the evolution of ${N_2}$ becomes two times faster when the initial concentration of the salt is doubled. Therefore, it is
Diazonium salt decomposes as ${C_6}{H_5}N_2^ + C{l^ - } \to {C_6}{H_5}Cl + {N_2}$ At ${0\,^o}C$, the evolution of ${N_2}$ becomes two times faster when the initial concentration of the salt is doubled. Therefore, it is
If the rate constant $(K)$ of a reaction is $1.6 \times 10^{-3}\, mol\, L^{-1}\, min^{-1}$ the order of reaction is
If the rate constant $(K)$ of a reaction is $1.6 \times 10^{-3}\, mol\, L^{-1}\, min^{-1}$ the order of reaction is
Order of radioactive disintegration reaction is
Order of radioactive disintegration reaction is