Green chemistry in day-to-day life

Chlorine gas was used earlier for bleaching paper. These days, hydrogen peroxide $\left(\mathrm{H}_{2} \mathrm{O}_{2}\right)$ with suitable catalyst.

Tetra chlroroethene $\left(\mathrm{Cl}_{2} \mathrm{C}=\mathrm{CCl}_{2}\right)$ was earlier used as solvent for dry cleaning. The compound contaminates the ground water and is also a suspected carcinogen. Replacement of halogenated solvent by liquid $\mathrm{CO}_{2}$ will result in less harm to groundwater.

Hence given statement (4) is correct.