What is atom economy? Explain any two applications of nanomaterials.

Answer: Atom economy measures how much of the reactants ends up in the desired product.

Atom economy: It is a principle of green chemistry stating that synthetic methods should be designed so that the maximum number of atoms of the reactants are incorporated into the final product, with minimum waste.

\(\%\ \text{atom economy} = \dfrac{\text{formula weight of desired product}}{\text{sum of formula weights of all reactants}} \times 100\)

Applications of nanomaterials (any two):

1. Medicine: nanoparticles are used for targeted drug delivery to diseased (e.g. cancer) cells, and in imaging and diagnosis.
2. Cosmetics / sunscreens: nano TiO₂ and ZnO are used in sunscreens; they block UV radiation and are transparent on the skin.
3. Electronics: nanomaterials give smaller, faster chips, better displays and high-density data storage.
4. Environment / textiles: nanosilver gives antibacterial, stain-resistant fabrics; nanomaterials are used for water purification and as catalysts.