Rate of gas production equals slope of volume-time curve

Steps:

• Identify the volume of gas (y-axis) versus time (x-axis) graph for both reactions.
• Determine the rate at each labeled point by calculating the slope (Δvolume/Δtime) of the tangent to the curve.
• Compare slopes: the greatest positive slope indicates the highest rate.
• Select the point with the steepest upward slope.

Why A is correct:

• Point A marks the initial steepest slope on one curve, where rate = maximum ΔV/Δt per rate law definition.

Why the others are wrong:

• B: Slope is less steep than A, indicating slower rate.
• C: Slope is flatter, showing even lower rate later in reaction.
• D: Near-zero or negative slope on the other curve means minimal or no production rate.

Final answer: A