Which of these statements is not true regarding reaction rate?

a. increasing particle size increases reaction rate.
b. raising the temperature increases reaction rate.
c. adding a catalyst increases reaction rate.
d. increasing concentration of the of reactants increases rate.

A. Increasing particle size increases reaction rate.

Explanation:

A. Increasing particle size increases reaction rate. S: If the particles are present in larger size, the surface area of the particles will be large and hence rate of reaction will be less.

B. Raising the temperature increases reaction rate : Increasing the temperature means more rate of reaction because the energy of the particles increases and more it can cross the energy barrier.

C. Adding a catalyst increases reaction rate: Catalyst is the substance which does not participate in the reaction but increases the rate of the reaction by lowering the activation energy.

D. Increasing concentration of the of reactants increases rate: According to rate law, the rate of the reaction is directly proportional to the concentration of reactants.