NO(g) + NO3(g) → 2 NO2(g) 47. The reaction between NO(g) and NO3(g) is represented by the equation a — Kinetics Chemistry Question

STEPS:

1. Understand the core chemical reaction:
The reaction is represented by the equation:
$$\text{NO}(g) + \text{NO}_3(g) \rightarrow 2\ \text{NO}_2(g) \quad$$
This process is an elementary bimolecular reaction that involves the transfer of a single oxygen atom from a dinitrogen trioxide precursor-like state in $\text{NO}_3$ to $\text{NO}$, yielding two identical nitrogen dioxide ($\text{NO}_2$) molecules.
2. Identify the molecular structure of the products:
A stable nitrogen dioxide ($\text{NO}_2$) molecule consists of a central nitrogen atom covalently bonded to two terminal oxygen atoms ($\text{O–N–O}$).
3. Determine the specific bond-forming and bond-breaking events:
* To successfully convert the reactant $\text{NO}$ into product $\text{NO}_2$, a new covalent bond must be formed directly on the electron-deficient nitrogen atom of the $\text{NO}$ molecule.
* This means the nitrogen atom of $\text{NO}$ must bond to the incoming oxygen atom being abstracted from $\text{NO}_3$.
* Simultaneously, the existing $\text{N–O}$ bond within the $\text{NO}_3$ reactant must be broken to release that oxygen atom.
4. Decode the particulate representations using the legend:
* In the molecular diagrams, the nitrogen (N) atoms are represented by the shaded (grey) spheres.
* The oxygen (O) atoms are represented by the unshaded (white) spheres.
* Therefore, the $\text{NO}$ reactant consists of one shaded sphere (N) and one unshaded sphere (O).
* The trigonal planar $\text{NO}_3$ reactant consists of a central shaded sphere (N) bonded to three terminal unshaded spheres (O).
5. Establish the correct collision orientation:
* According to collision theory, reactant molecules must collide in a specific spatial alignment that allows the reacting atoms to interact directly.
* For this reaction to be effective, the nitrogen atom of $\text{NO}$ (shaded sphere) must collide directly with one of the terminal oxygen atoms of $\text{NO}_3$ (unshaded sphere).
* Looking at the choices, Option D represents the nitrogen of $\text{NO}$ (shaded sphere) pointing directly at and colliding with a terminal oxygen of $\text{NO}_3$ (unshaded sphere), making it the only orientation likely to result in a successful chemical reaction.

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WHY_OTHERS_WRONG:

• Option A is incorrect: This diagram shows the oxygen atom (unshaded sphere) of $\text{NO}$ colliding with the central nitrogen atom (shaded sphere) of $\text{NO}_3$. This alignment is highly ineffective because it does not allow the reactive nitrogen of $\text{NO}$ to access an oxygen atom, and the central nitrogen of $\text{NO}_3$ is sterically shielded by its surrounding oxygen atoms.
• Option B is incorrect: This diagram shows the oxygen atom (unshaded sphere) of $\text{NO}$ colliding with a terminal oxygen atom (unshaded sphere) of $\text{NO}_3$. An oxygen-oxygen collision would attempt to form an unstable peroxyl-like linkage ($\text{N–O–O–NO}_2$) which is thermodynamically unfavorable and does not lead to the formation of the $\text{NO}_2$ products.
• Option C is incorrect: This diagram shows the nitrogen atom (shaded sphere) of $\text{NO}$ colliding with the central nitrogen atom (shaded sphere) of $\text{NO}_3$. Because the central nitrogen atom in $\text{NO}_3$ is fully surrounded and sterically protected by three outer oxygen atoms, a direct nitrogen-nitrogen collision is physically prevented and does not facilitate the required oxygen atom transfer.