Measuring Reaction Rate via Gas Production or Mass Loss

Steps:

• Reaction CaCO3 + 2HCl → CaCl2 + H2O + CO2 produces CO2 gas; rate measured by gas volume or mass loss over time with stopwatch.
• Set 1 uses gas syringe to collect and measure CO2 volume directly against time.
• Set 2 uses balance to track mass decrease from CO2 escape over time.
• Set 3 lacks direct gas volume or mass measurement, unsuitable for rate tracking.

Why B is correct:

• Sets 1 and 2 align with rate law definition: rate ∝ Δ[product]/Δt, where gas volume or mass loss quantifies CO2 production proportionally.

Why the others are wrong:

• A includes unsuitable set 3, which cannot track gas evolution.
• C omits set 1, missing a valid gas volume method.
• D includes unsuitable set 3 and omits set 1, lacking full valid options.

Final answer: B