Gas Behavior Under Temperature Changes

Steps:

• Evaluate statement 1: At constant pressure, Charles's Law (V ∝ T) shows volume increases with temperature.
• Evaluate statement 2: Higher temperature increases molecular kinetic energy, speeding up diffusion per Graham's Law extension.
• Evaluate statement 3: At constant volume, Gay-Lussac's Law (P ∝ T) shows pressure increases with temperature, not decreases.
• Conclude: Statements 1 and 2 are correct; 3 is incorrect.

Why B is correct:

• B selects 1 and 2 only, aligning with Charles's Law for volume and kinetic theory for diffusion rate.

Why the others are wrong:

• A includes 3, which contradicts Gay-Lussac's Law (P increases with T at constant V).
• C omits 2, ignoring temperature's effect on diffusion speed.
• D omits 1, violating Charles's Law.

Final answer: B