Factors Affecting Gaseous Reaction Rates

Steps:

• Reaction rates for gases follow collision theory: rate increases with more frequent and energetic molecular collisions.
• Increasing pressure raises gas concentration, boosting collision frequency without changing volume.
• Increasing temperature elevates molecular kinetic energy, increasing the fraction of collisions with sufficient activation energy.
• Increasing volume lowers concentration (at constant moles), reducing collision frequency and thus the rate.

Why B is correct:

• Collision theory states that pressure and temperature directly enhance collision frequency and effectiveness, accelerating the reaction rate.

Why the others are wrong:

• A includes 3, but larger volume decreases concentration and collisions, slowing the rate.
• C includes 3 (decreases rate) and excludes 2 (which increases rate via higher energy).
• D excludes 1 (which increases rate via concentration) and includes 3 (which decreases rate).

Final answer: B