Question

At constant temperature, a gas occupies a volume of 200 mL at a pressure of 500 mm Hg. What will be its volume at 800 mm Hg pressure?

• A. \(280 \text{mL}\)
• B. \(125 \text{mL}\)
• C. \(100 \text{mL}\)
• D. \(350 \text{mL}\)

Hint:

At constant temperature, pressure times volume stays constant.

Answer 1

The Correct Option is B

Step 1: Use the ratio form
For constant temperature, $V_2 = V_1 \times \frac{P_1}{P_2}$.

Step 2: Evaluate
The pressure ratio is $\frac{500}{800} = 0.625$. Then $V_2 = 200 \times 0.625 = 125$ mL.

Step 3: Conclusion
The volume shrinks to 62.5 percent of the original, which is 125 mL. This is option (B).

Final Answer:
Volume becomes 125 mL. \[ \boxed{\text{(B)}\ 125\ \text{mL}} \]