How will the lowering of temperature affect the chemical equilibrium in the system
`2NO+O_(2)hArr2NO_(2), Delta H lt 0`

Options

A. Relative concentration of products and reactants does not change.
B. Relative concentration of products and reactants change.
C. Equilibrium is shift to the left.
D. Equilibrium is shift to the right.

Explanation

To solve the problem regarding how the lowering of temperature affects the chemical equilibrium of the reaction:

**Reaction:**
\[ 2NO + O_2 \rightleftharpoons 2NO_2 \]
**ΔH < 0** (indicating that the reaction is exothermic)

### Step-by-Step Solution:

1. **Identify the Nature of the Reaction:**
- The given reaction is exothermic because ΔH is less than zero. This means that heat is released when the reaction proceeds in the forward direction (from reactants to products).

**Hint:** Remember that exothermic reactions release heat, while endothermic reactions absorb heat.

2. **Apply Le Chatelier's Principle:**
- Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in conditions (such as temperature), the equilibrium will shift in a direction that counteracts the change.

**Hint:** Think of the equilibrium as a balance that will shift to restore stability when disturbed.

3. **Consider the Effect of Lowering Temperature:**
- Lowering the temperature in an exothermic reaction will favor the formation of products because the system will try to produce more heat to counteract the decrease in temperature.

**Hint:** For exothermic reactions, reducing temperature shifts the equilibrium towards the products.

4. **Determine the Direction of the Shift:**
- Since the reaction is exothermic, lowering the temperature will shift the equilibrium to the right (towards the production of NO2).

**Hint:** Visualize the reaction: if heat is a product, removing heat (by lowering temperature) will encourage the reaction to produce more products.

5. **Evaluate the Options:**
- Based on the analysis:
- Option 1: Relative concentration of products and reactants does not change - **Incorrect.**
- Option 2: Relative concentration of products and reactants change - **Correct.**
- Option 3: Equilibrium shifts to the left - **Incorrect.**
- Option 4: Equilibrium shifts to the right - **Correct.**

**Hint:** Always check if the options align with the conclusions drawn from Le Chatelier's Principle.

### Final Conclusion:
- The correct answer is that lowering the temperature will shift the equilibrium to the right, favoring the formation of NO2.