AP Chemistrymediummcq1 pt
A substance is consumed in the first step of a mechanism and regenerated in the last. What is it?
A.A catalyst
B.An intermediate
C.A reactant
D.A product
Explanation
Core Concept
Catalysts enter the mechanism, get consumed, and reform by the end — net unchanged. That consumption-then-regeneration pattern identifies them.
Correct Answer
AA catalyst
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