A stockroom supervisor measured the contents of a partially filled 25.0 gallon acetone drum on a day when the temperature was `18^(@)C` and atmospheric pressure was 780 mm Hg and found that 15.4 gallon of the solvent remained. After tightly sealing the drum a student assistant dropped the drum while carrying it upstairs to the organic laboratory. The drum was dented and its internal volume was decreased to 20.4 gallon. What is the total pressure inside the drum volume was decreased to 20.4 gallon. What is the total pressure inside the drum after the accident ? The vapour pressure of acetone at `18^(@)C` is 400 mm Hg.

Explanation

To solve the problem, we will use the ideal gas law concept and the relationship between pressure and volume. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Initial Conditions
- The initial volume of the drum (V1) is 25.0 gallons.
- The volume of acetone remaining is 15.4 gallons.
- The available volume for the gas is \( V1 - \text{volume of liquid} = 25.0 \, \text{gallons} - 15.4 \, \text{gallons} = 9.6 \, \text{gallons} \).
- The atmospheric pressure (P1) is 780 mm Hg.
- The vapor pressure of acetone at 18°C is 400 mm Hg.
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