Boyle's Law for constant temperature

Steps:

• Initial gas pressure is atmospheric (100 kPa) plus 200 kPa, so 300 kPa.
• Volume doubles while temperature stays constant, so use Boyle's law: P1 V1 = P2 V2.
• Substitute: 300 kPa × V1 = P2 × 2 V1.
• Solve for P2: P2 = 300 kPa / 2 = 150 kPa.

Why B is correct:

• Boyle's law states that pressure inversely proportional to volume at constant temperature, halving pressure when volume doubles.

Why the others are wrong:

• A ignores initial excess pressure, assuming equilibrium with atmosphere.
• C assumes pressure unchanged, violating Boyle's law.
• D doubles pressure, confusing it with volume halving instead.

Final answer: B