Which of the following gases will have equal volume at STP, if the weight of gases is 14.0 g ?
(i) `N_2O` (ii) `NO_2`
(iii) `N_2` (iv) CO

Options

A. (i) & (ii)
B. (ii) & (iii)
C. (i) & (iii)
D. (iii) & (iv)

Explanation

To determine which of the given gases will have equal volume at STP (Standard Temperature and Pressure) when the weight of each gas is 14.0 g, we need to follow these steps:

### Step 1: Calculate the number of moles for each gas
To find the number of moles, we use the formula:
\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]
We will calculate the number of moles for each gas using their respective molar masses.

### Step 2: Find the molar masses of the gases
- **N₂O (Nitrous oxide)**:
- Molar mass = 14 (N) + 14 (N) + 16 (O) = 44 g/mol
- **NO₂ (Nitrogen dioxide)**:
- Molar mass = 14 (N) + 16 (O) + 16 (O) = 46 g/mol
- **N₂ (Nitrogen)**:
- Molar mass = 14 (N) + 14 (N) = 28 g/mol
- **CO (Carbon monoxide)**:
- Molar mass = 12 (C) + 16 (O) = 28 g/mol

### Step 3: Calculate the number of moles for each gas
- For **N₂O**:
\[ \text{Number of moles} = \frac{14.0 \, \text{g}}{44 \, \text{g/mol}} \approx 0.318 \, \text{moles} \]
- For **NO₂**:
\[ \text{Number of moles} = \frac{14.0 \, \text{g}}{46 \, \text{g/mol}} \approx 0.304 \, \text{moles} \]
- For **N₂**:
\[ \text{Number of moles} = \frac{14.0 \, \text{g}}{28 \, \text{g/mol}} = 0.500 \, \text{moles} \]
- For **CO**:
\[ \text{Number of moles} = \frac{14.0 \, \text{g}}{28 \, \text{g/mol}} = 0.500 \, \text{moles} \]

### Step 4: Determine the volume at STP
At STP, 1 mole of any gas occupies 22.4 liters. Therefore, the volume for each gas can be calculated as follows:
- For **N₂O**:
\[ \text{Volume} = 0.318 \, \text{moles} \times 22.4 \, \text{L/mol} \approx 7.13 \, \text{L} \]
- For **NO₂**:
\[ \text{Volume} = 0.304 \, \text{moles} \times 22.4 \, \text{L/mol} \approx 6.81 \, \text{L} \]
- For **N₂**:
\[ \text{Volume} = 0.500 \, \text{moles} \times 22.4 \, \text{L/mol} = 11.20 \, \text{L} \]
- For **CO**:
\[ \text{Volume} = 0.500 \, \text{moles} \times 22.4 \, \text{L/mol} = 11.20 \, \text{L} \]

### Step 5: Compare the volumes
From the calculations:
- N₂O: 7.13 L
- NO₂: 6.81 L
- N₂: 11.20 L
- CO: 11.20 L

### Conclusion
The gases that will have equal volume at STP when the weight is 14.0 g are **N₂** and **CO**, both occupying 11.20 L.

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