Reaction rate depends on surface area and acid concentration

Steps:

• Large magnesium pieces (exp 1) limit surface area, slowing reaction rate compared to small pieces.
• Small pieces (exp 2) increase surface area, accelerating reaction rate most.
• Higher acid concentration (exp 3) boosts rate despite large pieces, but less than small pieces.
• Match graphs: slowest curve (Y) to exp 1, fastest (W) to exp 2, medium (X) to exp 3.

Why D is correct:

• D assigns Y (slowest) to exp 1 (low surface area), X (medium) to exp 2 (high surface area, standard acid), W (fastest) to exp 3 (low surface area, high concentration), aligning with collision theory where rate increases with more frequent effective collisions.

Why the others are wrong:

• A mismatches by assigning fastest (W) to slowest exp 1.
• B swaps exp 1 and 2, ignoring surface area effect.
• C assigns slowest (X) to exp 2, contradicting increased surface area.

Final answer: D