Avogadro's lasw states that under conditions of constant temp. and pressure equal volume of gases contain equal no. of particles. Experimental investigation shows that at one atmosphere pressure and a temperature of 273 k, one mole of any gas occupies a volume of which is very close to 22.4 lit. Therefore, the number of moles in any gas sample canbe found by comparing its volume at STP with 22.4 lit.
At STP 40 lit of `CO_(2)` contains

Options

A. 5.6 mole
B. 1.786 mole
C. 7.635 mole
D. 1.934 mole

Answer

To determine the number of moles in 40 liters of carbon dioxide (CO₂) at standard temperature and pressure (STP), we can use Avogadro's law, which states that equal volumes of gases at the same temperature and pressure contain an equal number of particles.

### Step-by-Step Solution:

1. **Understand the Volume at STP**:
At STP (Standard Temperature and Pressure), which is defined as 273 K (0°C) and 1 atm pressure, one mole of any ideal gas occupies a volume of approximately 22.4 liters.

2. **Identify the Given Volume**:
The problem states that we have 40 liters of CO₂.

3. **Set Up the Proportion**:
We know that 22.4 liters of CO₂ corresponds to 1 mole. To find the number of moles in 40 liters, we can set up the following proportion:
\[ \text{Number of moles} = \frac{\text{Volume of gas (liters)}}{\text{Volume of 1 mole of gas (liters)}} \]
Here, the volume of 1 mole of gas at STP is 22.4 liters.

4. **Calculate the Number of Moles**:
Substitute the values into the equation:
\[ \text{Number of moles} = \frac{40 \text{ liters}}{22.4 \text{ liters/mole}} \]
Now, perform the calculation:
\[ \text{Number of moles} = \frac{40}{22.4} \approx 1.786 \text{ moles} \]

5. **Conclusion**:
Therefore, at STP, 40 liters of carbon dioxide contains approximately 1.786 moles.

### Final Answer:
At STP, 40 liters of CO₂ contains approximately **1.786 moles**.

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