Green chemistry in day-to-day life is in the use of:

Green chemistry aims to reduce or eliminate the use of hazardous substances in chemical processes. The correct answer is option 4: liquified $$\text{CO}_2$$ for dry cleaning of clothes.

Let us evaluate each option. Chlorine used for bleaching paper is harmful as it produces toxic byproducts such as dioxins and chlorinated compounds, making it environmentally unfriendly. Using a large amount of water alone for washing clothes is wasteful of a precious natural resource, which contradicts green chemistry principles. Tetrachloroethene (perchloroethylene) used in dry cleaning is a volatile organic compound that is toxic and a suspected carcinogen, and it contaminates groundwater — exactly the kind of substance green chemistry seeks to replace.

Liquified $$\text{CO}_2$$ as a solvent for dry cleaning is the green chemistry alternative. $$\text{CO}_2$$ is non-toxic, non-flammable, and the carbon dioxide used is often a byproduct of existing industrial processes, so its use does not add net carbon to the atmosphere. It is an excellent solvent that leaves no harmful residues and is easily recycled in a closed-loop system. This makes it the best example of green chemistry in day-to-day life among the given options.

The correct answer is option 4.