Concept:In a chemical reaction involving multiple reactants, they are rarely mixed in exact stoichiometric perfection. The one that runs out first halts the entire reaction.
Formula:$$ \text{Reaction stops when Limit} = 0 $$
Solution:- The reactant that is entirely consumed first is scientifically termed the Limiting Reactant.
- Because it runs out early, it strictly limits and determines the maximum theoretical yield of the product that can be formed.
Why other options are incorrect:- Excess reactant: This is the exact opposite; it is the reactant that is left over unreacted after the limiting reactant is completely gone.
- Active / More active reactant: These are vague, non-standard terms usually referring to kinetic reactivity or position on the activity series, completely unrelated to stoichiometric amounts.
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