Question

For a chemical reaction to occur, all of the following must happen except.
A.A large enough number of collisions must occur
B.Chemical bonds in the reactants must break
C.Reactant particles must collide which enough energy for change to occur
D.Reactant particles must collide with correct orientation

Answer 1

Hint: To determine whether a chemical reaction will take place we need to consider the activation energy of the reaction, temperature at which the reaction is taking place and other factors including the type of collision between the reactant molecules. The collision theory throws light on the collision of molecules in a reaction.

Complete step by step answer:
-In a chemical reaction the conversion of one compound into another takes place. The compounds that react are called the reactants and the compounds formed as a result of this reaction are known as products.
-For the conversion of reactants into products, the pre-existing bonds in the reactant molecules must break so that the formation of new bonds can take place.
Energy is required for the cleavage of bonds which is either provided to the reactants by increasing the temperature or it is gained by the collision of reactant molecules with each other.
-The collision theory states that a reaction can take place only if the reactant molecules collide with each other. The collisions must have sufficient energy to break the bonds in the reactant molecules in order to initiate the reaction.
-These collisions can provide sufficient energy only if the molecules collide effectively which can be achieved with proper orientation of the molecules.
-So, options B, C and D are necessary conditions for a reaction to take place.

Therefore, option A is the answer as there is no such condition for large enough collisions to take place for a reaction to occur.

Note:
We have learnt that by increasing the temperature we provide energy required for the reaction to occur because according to collision theory increasing the temperature of the reaction increases the kinetic energy of the molecules, which makes the molecules to move faster and in turn increases the number of collisions.