Two oxides of Nitrogen, NO and NO, react together at 253K and form a compound of Nitrogen, 'x'. 'x' reacts with water to yield another compound of Nitrogen, 'y'. The shape of the anion of 'y' molecule is 

Options

A. Tetrahedral
B. Angular
C. Square planar
D. Pyramidal

Answer

To solve the question step by step, we will analyze the reaction between the nitrogen oxides and determine the shape of the anion of the resulting compound.

### Step 1: Identify the Reactants
We start with two oxides of nitrogen: NO (nitric oxide) and NO2 (nitrogen dioxide).

### Step 2: Determine the Reaction
At 253 K, these two oxides react together. The likely reaction between NO and NO2 is:
\[ 2 \text{NO} + \text{NO}_2 \rightarrow \text{N}_2\text{O}_3 \]
Here, the product formed is \( \text{N}_2\text{O}_3 \), which we will refer to as compound 'x'.

### Step 3: React Compound 'x' with Water
Next, we need to react \( \text{N}_2\text{O}_3 \) with water. The reaction can be represented as:
\[ \text{N}_2\text{O}_3 + 3 \text{H}_2\text{O} \rightarrow 2 \text{HNO}_2 \]
This means that compound 'y' is \( \text{HNO}_2 \) (nitrous acid).

### Step 4: Identify the Anion of Compound 'y'
The anion formed from \( \text{HNO}_2 \) when it dissociates in water is \( \text{NO}_2^- \) (nitrite ion).

### Step 5: Determine the Shape of the Anion
To determine the shape of the nitrite ion \( \text{NO}_2^- \), we can use VSEPR theory. The nitrite ion has:
- 1 nitrogen atom bonded to 2 oxygen atoms.
- The nitrogen atom has a lone pair of electrons.

The arrangement of the electron pairs (1 lone pair and 2 bonding pairs) leads to a bent or angular shape.

### Conclusion
The shape of the anion \( \text{NO}_2^- \) is angular.

### Final Answer
The shape of the anion of compound 'y' is **angular**.

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