In `NH_3` synthesis by Haber's process, what is the effect on the rate of the reaction with the addition of Mo and CO, respectively?

Options

A. Increases and decreases
B. Decreases and decreases
C. Decreases and increases
D. Both Mo and Co increases the rate

Answer

To analyze the effect of Mo (Molybdenum) and CO (Carbon Monoxide) on the rate of the NH3 synthesis reaction in the Haber process, we can break down the solution into the following steps:

### Step 1: Understand the Haber Process
The Haber process is a method for synthesizing ammonia (NH3) from nitrogen (N2) and hydrogen (H2) gases. The reaction can be represented as:
\[ N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) \]

### Step 2: Identify the Role of Catalysts
In the Haber process, iron (Fe) is commonly used as a catalyst to speed up the reaction without being consumed. Catalysts work by providing an alternative reaction pathway with a lower activation energy.

### Step 3: Effect of Molybdenum (Mo)
Molybdenum is known to act as a catalyst activator. When Mo is added to the reaction, it enhances the activity of the iron catalyst. This means that the presence of Mo will increase the rate of the reaction because it improves the efficiency of the catalyst.

### Step 4: Effect of Carbon Monoxide (CO)
On the other hand, Carbon Monoxide is a known catalyst poison. When CO is introduced into the reaction, it tends to bind to the active sites of the catalyst (iron), thereby reducing its effectiveness. This results in a decreased rate of the reaction because the catalyst is less able to facilitate the conversion of reactants to products.

### Step 5: Conclusion
In summary:
- The addition of Molybdenum (Mo) increases the rate of the NH3 synthesis reaction.
- The addition of Carbon Monoxide (CO) decreases the rate of the NH3 synthesis reaction.

### Final Answer:
- Effect of Mo: Increases the rate of reaction.
- Effect of CO: Decreases the rate of reaction.