30 litre of ammonia gas at `30^@C` and 40 atm pressure is allowed to expand in a space of 40 litre capacity and pressure becomes 20 atm. Calculate the drop in temperature.

Explanation

To solve the problem of calculating the drop in temperature of ammonia gas when it expands, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Initial volume, \( V_1 = 30 \, \text{liters} \)
- Initial temperature, \( T_1 = 30^\circ C = 303 \, \text{K} \) (convert to Kelvin by adding 273)
- Initial pressure, \( P_1 = 40 \, \text{atm} \)
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