Chemistry??

Question

For the reaction

Mo(CO)6 + P(CH3)3 --> Mo (CO)5P(CH3)3+CO

the proposed mechanism is

Mo(CO)6--> Mo(CO)5 + CO

Mo(CO)5 + P(CH3)3-->Mo (CO)5P(CH3)3

 

(a) Is the proposed mechanism consistent with the equation for the overall reaction?

(b) What is the molecularity of each step of the mechanism?

(c) Identify the intermediate(s). 

 

Answer 1

Step 1:

(a)

The chemical equation is .

The proposed mechanism is

Consider the two elementary steps as follows:

Add the two elementary reactions.

As  appears in equal amount on the both sides of the reaction, it can be eliminated.

.

Hence, the proposed mechanism can yield the chemical equation.

Step 2:

(b)

Molecularity:

The molecularity of a reaction is defined as the number of molecules or ions that participate in the rate determining step.

The molecularity of first elementary step is unimolecular since only one molecule is involved in rate determining step.

The molecularity of second elementary step is bimolecular since only two molecules and are involved in rate determining step.

Hence, first elementary step is unimolecular and second elementary step is bimolecular.

Step 3:

(c)

Chemical intermediate:

Any chemical substance produced during the conversion of some reactant to a product is intermediate.

Here is produced during the conversion.

is the chemical intermediate.

Solution:

(a) Yes, the proposed mechanism can yield the chemical equation.

(b) First elementary step is unimolecular and second elementary step is bimolecular.

(c) is the chemical intermediate.