Chapter 9.6, Problem 3QQ

Interpretation Introduction

Interpretation:

The correct option for the given statement has to be chosen.

Concept Introduction:

Rate of a Chemical Reaction:

It is the rate of change of concentration of reactant or product per unit time or it is expressed in by decrease in concentration of reactant or increase in concentration of product.

Factors affecting the rate of a chemical reaction:

1. 1. Concentration of Reactants:

Rate of the reaction is directly proportional to concentration of the reactants.

    ${\text{r=kc}}^{\text{n}}$

    c = concentration

    n = order of the reaction

    k = specific rate

1. 2. Reaction Temperature:

Increase in temperature will increase the average kinetic energy of the reactant molecules.  It is very easy for the molecules to move and thus makes the collision more effective.  A large fraction of collisions will result in the product.

1. 3. Presence of Catalysts:

Catalyst is a substance which can increase the rate of the reaction without altering the reaction.  It will provide an alternative pathways for the reaction, thereby lowering the activation energy.  For attaining equilibrium in a reversible process, the catalyst will lowers the activation energies of both forward and backward reactions.

Activation Energy:

For a reaction to occur, the reactant molecules must collide with some minimum amount of energy.  This minimum amount of energy for a reaction to occur is known as activation energy.  Every reaction will have different activation energy.  Activation energy is dependent on temperature.  As the temperature increases, molecules will move faster and the activation energy decreases.