Question

what is the condition of chemical reaction

Answer 1

In order for a chemical reaction to occur, three conditions must first be met. These considerations are the basic principles of Collision Theory. In most cases, two molecules must collide in order to react. Such a step is defined as bimolecular, because it involves two molecules.

Answer 2

there should be atleast two reactants
there should be suitable temperature in atmosphere
if heat is needed, it should be provided.