Question

How many types of reaction are there on the basis of speed\[?\]

Answer 1

Hint: Increasing the number of collisions speeds up the reaction rate. The more reactant molecules there are colliding, the faster the reaction will be. In most simple cases, increasing the concentration of the reactants increases the speed of the reaction.

Complete answer:
On the basis of speed there are two types of reaction fast reaction and slow reaction .
Slow reaction:
There are certain reactions which are extremely slow and might take months to show any measurable change at room temperature. It is also difficult to study the kinetics of such reactions. The reactions between covalent compounds are slow. For example rusting of iron, weathering of rocks, fermentation of sugar into ethyl alcohol and carbon dioxide etc.
 Fast reaction:
A fast reaction is defined as one whose half-life is less than a few seconds (that is, of the same order as the human response time or the mixing time for reactants) at room temperature using conventional reactant concentrations. These are those chemical reactions which take place at a very fast rate. For example, combustion of $LPG$ gas in the kitchen takes place in a few seconds so it is a fast reaction. In the same way reaction of an acid like $HCl$ with a base such as $NaOH$ takes place in seconds to produce a salt $NaCl$ and water is a very fast reaction.

Note:
 The rates of fast reaction cannot be determined easily. Ionic compounds in solution react faster than molecular compounds. This is because Ionic compounds break apart to form free ions. Therefore, there are no bonds to break so the reaction is fast.