JEE Main & Advanced Chemistry Chemical Kinetics / रासायनिक बलगतिकी Types Of Chemical Reactions

On the basis of reaction rates, the chemical reactions have been classified into the following three types,

(1) Very fast or instantaneous reactions : These reactions occur at a very fast rate generally these reactions involve ionic species and known as ionic reactions. It is almost impossible to determine the rates of these reactions.

Examples    

 (i) \[AgN{{O}_{3}}+NaCl\to \underset{\text{(PPt}\text{.)}}{\mathop{AgCl}}\,+NaN{{O}_{3}}\] (Precipitation reaction)

           (ii) \[\underset{\text{(acid)}}{\mathop{HCl}}\,+\underset{\text{(base)}}{\mathop{NaOH}}\,\to \underset{\text{(Salt)}}{\mathop{NaCl}}\,+{{H}_{2}}O\]  (Neutralization reaction)

(2) Moderate reaction : These reactions proceed with a measurable rates at normal temperature and it is these reactions are studied in chemical kinetics. Mostly these reactions are molecular in nature.

Examples

(i) Decomposition of \[{{H}_{2}}{{O}_{2}}\]: \[2{{H}_{2}}{{O}_{2}}\to 2{{H}_{2}}O+{{O}_{2}}\]

(ii) Decomposition of \[{{N}_{2}}{{O}_{5}}\]: \[2{{N}_{2}}{{O}_{5}}\to 2{{N}_{2}}{{O}_{4}}+{{O}_{2}}\]

(3) Very slow reactions : These reactions are extremely slow and take months together to show any measurable change.

Examples

(i) Rusting of iron : \[F{{e}_{2}}{{O}_{3}}+x{{H}_{2}}O\to \underset{\text{Hydrated ferric oxide (Rust)}}{\mathop{F{{e}_{2}}{{O}_{3}}.\,x{{H}_{2}}O}}\,\]

(ii) \[2{{H}_{2}}+{{O}_{2}}\xrightarrow{\text{Room temperature}}2{{H}_{2}}O\]