Two oxides of Nitrogen, NO and `NO_(2)` reacts together at 253 K and form a compound Nitrogen X.X reacts with water to yield another compound of Nitrogen Y. The shape of the anion of Y molecule is

Options

A. triangular planar
B. triangular pyramidal
C. tetrahedron
D. square planar

Explanation

To solve the problem step by step, we will analyze the reactions and compounds formed:

### Step 1: Identify the Reaction Between NO and NO2
The two oxides of nitrogen, NO (nitric oxide) and NO2 (nitrogen dioxide), react together at 253 K. The reaction can be represented as follows:

\[ 2 \text{NO} + \text{NO}_2 \rightarrow \text{N}_2\text{O}_3 \]

### Step 2: Identify Compound X
From the reaction above, we can see that the product formed is \( \text{N}_2\text{O}_3 \). Thus, the compound X is:

\[ \text{X} = \text{N}_2\text{O}_3 \]

### Step 3: Reaction of Compound X with Water
Next, we need to determine what happens when \( \text{N}_2\text{O}_3 \) reacts with water. The reaction can be represented as:

\[ \text{N}_2\text{O}_3 + \text{H}_2\text{O} \rightarrow 2 \text{HNO}_2 \]

Here, \( \text{HNO}_2 \) is nitrous acid, which is the compound Y.

### Step 4: Identify the Structure of Compound Y
The structure of nitrous acid \( \text{HNO}_2 \) can be drawn as follows:

- Nitrogen (N) is bonded to one hydroxyl group (–OH) and has a double bond with one oxygen (O).
- The remaining oxygen carries a negative charge.

The structural formula can be represented as:

\[ \text{HNO}_2: \quad \text{O} \quad \text{N} \quad \text{O}^- \]

### Step 5: Determine the Shape of the Anion of Y
The anion of \( \text{HNO}_2 \) is \( \text{NO}_2^- \). To determine its shape, we need to consider the hybridization and geometry:

- The nitrogen atom in \( \text{NO}_2^- \) has one lone pair and forms two bonds (one double bond with one oxygen and one single bond with another oxygen).
- The hybridization of nitrogen in this case is \( \text{sp}^2 \) because it has three regions of electron density (two bonds and one lone pair).

### Step 6: Conclusion on the Shape
The geometry of \( \text{NO}_2^- \) is trigonal planar due to the \( \text{sp}^2 \) hybridization, which means the shape of the anion is planar.

### Final Answer
The shape of the anion of Y (which is \( \text{NO}_2^- \)) is trigonal planar.

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