Consider the following sequence of conversion.
`underset((X))ubrace(2NO+O_(2)) Leftrightarrow underset((Y))(2NO_(2)) underset("heat")overset("cool")Leftrightarrow underset((Z))(N_(2)O_(4))`
X, Y and Z can be described as

Options

A. 1. `{:("X","Y","Z"),("Colourless","Brown paramagnetic"," Colourless diamagnetic"):}`
B. 2. `{:("X","Y","Z"),("Brown","Colourless diamagnetic","Brown paramagnetic"):}`
C. 3. `{:("X","Y","Z"),("Colourless","Colourless, paramagnetic","Brown diamagnetic"):}`
D. 4. `{:("X","Y","Z"),("Brown","Brown paramagnetic","Brown diamagnetic"):}`

Explanation

To solve the problem, we will analyze the sequence of conversions provided and characterize the substances X, Y, and Z based on their properties.

### Step-by-step Solution:

1. **Identify the substances:**
- The first substance (X) is formed from the reaction of nitrogen monoxide (NO) and oxygen (O2). The reaction is:
\[ 2NO + O_2 \rightarrow 2NO_2 \]
- The second substance (Y) is nitrogen dioxide (NO2), which is produced from the reaction above.
- The third substance (Z) is dinitrogen tetroxide (N2O4), which is formed from the cooling of NO2:
\[ 2NO_2 \leftrightarrow N_2O_4 \]

2. **Characterize Substance X (NO):**
- Nitric oxide (NO) is a colorless gas. It is a free radical with an unpaired electron, which makes it paramagnetic.

3. **Characterize Substance Y (NO2):**
- Nitrogen dioxide (NO2) is a brown gas. It is also an odd-electron molecule, meaning it has an unpaired electron, which contributes to its paramagnetic nature.

4. **Characterize Substance Z (N2O4):**
- Dinitrogen tetroxide (N2O4) is a dimer of NO2. It is colorless and is diamagnetic because it has no unpaired electrons.

5. **Summarize the characteristics:**
- **X (NO)**: Colorless, paramagnetic
- **Y (NO2)**: Brown, paramagnetic
- **Z (N2O4)**: Colorless, diamagnetic

6. **Conclusion:**
- Based on the properties identified, we can describe X, Y, and Z as follows:
- X: Colorless, paramagnetic (NO)
- Y: Brown, paramagnetic (NO2)
- Z: Colorless, diamagnetic (N2O4)

### Final Answer:
- X is colorless and paramagnetic (NO), Y is brown and paramagnetic (NO2), and Z is colorless and diamagnetic (N2O4).