Which law states that pressure and volume are inversely related at constant temperature?

• A. Charles' Law
• B. Boyle's Law
• C. Gay-Lussac's Law
• D. Avogadro's Law

Answer: (B)

At constant temperature and a fixed amount of gas, pressure and volume are inversely related. This is Boyle’s law, which comes from the ideal gas relation PV = nRT. With n (amount of gas), R, and T held constant, the product PV remains constant, so if you decrease the volume, the pressure must increase, and if you increase the volume, the pressure drops. This inverse relationship is why squeezing a balloon (reducing V) raises its internal pressure.

Other laws describe different pairings: Charles’ law concerns volume changing with temperature at constant pressure, Gay-Lussac’s law links pressure with temperature at constant volume, and Avogadro’s law relates volume to the amount of gas at fixed pressure and temperature.