Question

What is limiting reagent? Explain with example.

Answer 1

A substance that does not allow a chemical reaction to take place completely is called the limiting reagent.
If a chemical reaction involves a limiting reagent , then the atoms/molecules/ions of the other reactant with which it (limiting reagent ) combines will remain free or will remain unreacted.

Eg: C + O -> CO
ie, 1 mol C + 1 mol O -> 1 mol CO

Consider that 24g C (2 moles) and 8g O (0.5 mole) are provided. From the given equation, it can be said that 0.5 moles of O can react only with 0.5 moles of C and this results in 0.5 moles of CO. Here, O is the limiting reagent as it cannot completely react with 2 moles of C to produce 2 moles of CO. Thus 1.5 moles of C will remain un reacted.