Respuesta :
The best answer among the choices listed is the third option. The rate over the course of a reaction decreases because the concentration of reactants decreases. As the concentration of the reactants decreases, there is less particles to form the products therefore less rate.
Answer: Option (c) is the correct answer.
Explanation:
Rate of reaction is defined as the speed of a chemical reaction.
When there is more number of collisions between reactant molecules then there will be increase in rate of a chemical reaction.
Also, when we increase the concentration of reactant molecules then it means there will be more number of molecules. This will lead to more number of collisions and as a result, there will be increase in the rate of a chemical reaction. Similarly, on decreasing the concentration of reactants there will be decrease in rate of reaction.
Also, when a chemical reaction progresses then it is not necessary that number of collisions will also increase.
Therefore, we can conclude that generally it is true about rate over the course of a reaction that rate decreases because the concentration of reactants decreases.