Question

so if a solution undergoes a chemical change with a another substance and loses its original chemical composition so that we will be considered mixture or impure substance or none

Answer 1

Ans That will be considered as a pure substance when a chemical reaction takes place .

Explanation:

as there is a chemical reaction taking place all particles in the substance are same .example iron and oxygen react to form Fe2o3 which is a pure substance as it has single type of particles as there is a compound formed .And a compound is a pure substance .