Q150 / 200 · MHT CET - Medical 2026 (24 April Shift 2) · Chemistry
Which of the following types exhibits $100\%$ atom economy?
- Correct answerAAddition
- BSubstitution
- CElimination
- DDehydrogenation
Solution
Atom economy is the measure of the proportion of reactant atoms that become part of the desired product in a chemical reaction.
$\text{Atom economy} = \dfrac{\text{Molecular mass of desired product}}{\text{Molecular mass of all reactants}} \times 100$
In an addition reaction, two or more reactants combine to form a single product. Since no by-products are formed, all the atoms of the reactants are incorporated into the product.
Thus, addition reactions exhibit $100\%$ atom economy.
In substitution, elimination, and dehydrogenation reactions, by-products are formed, leading to an atom economy of less than $100\%$.
Answer: Addition
$\text{Atom economy} = \dfrac{\text{Molecular mass of desired product}}{\text{Molecular mass of all reactants}} \times 100$
In an addition reaction, two or more reactants combine to form a single product. Since no by-products are formed, all the atoms of the reactants are incorporated into the product.
Thus, addition reactions exhibit $100\%$ atom economy.
In substitution, elimination, and dehydrogenation reactions, by-products are formed, leading to an atom economy of less than $100\%$.
Answer: Addition
Hence, the correct answer is option: 'A'.