Question

The rate of chemical reaction at constant temperature is proportional to which of the following:
A.The amount of product formed
B.The product of masses of reactants
C.The product of the molar concentration of the reactants
D.The mean free path of the reaction

Answer 1

First of all we have to find out the factors which affect the rate of chemical reaction. By using the law of mass action, we can find the solution to this question.

Complete step by step answer:
The speed at which the reactants are converted to products is called the rate of reaction. There are many factors which affects the speed of conversion of reactants into products –
Nature of reaction: The state and number of reactants and complexity of reaction can affect the rate of reaction.
Effect of concentration: From the law of mass action, the rate of reaction is directly proportional to the concentration of reactants, that is, rate of reaction increases with the increase in concentration of reactants.
Pressure: The concentration of reactants can be increased by the pressure. Hence, when pressure is increased the speed of reaction also increases.
Catalyst: It can increase speed in both reverse and forward direction. This gives another path having low activation energy.
Temperature: The reaction which takes place at high temperature has more energy than reaction at low temperature.
Now, we have to know what the law of mass action states which will give us the clearer answer to this question.
Therefore, according to the law of mass action, “the rate of the chemical reaction is directly proportional to the product of the activities or concentrations of the reactants”. So, from this statement we can conclude that the rate of reaction depends upon the concentrations of the reactants which increase the speed of reaction with the increase in chemical reaction.
Hence the correct option is C.

Note:
One must note that, in the question, the factor(s) affecting the rate of reaction at constant temperature were asked. There are many other factors which affect the rate of reaction if constant temperature is not given as a constraint. The rate of reaction also depends on the physical state of the reactants, surface area and catalyst including temperature.