For dry cleaning, in the place of tetrachloroethane, liquefied carbon dioxide with suitable detergent is an alternative solvent. What type of harm to the environment will be prevented by stopping use of tetrachloroethane? Will use of liquefied carbon dioxide with detergent be completely safe from the point of view of pollution? Explain

Explanation

Tetrachloroethene `(C1_2C = C Cl_2)` has earlier been used as a solvent for dry cleaning. This compound is suspected to be carcinogenic and contaminates the ground water. This harmful effect has not been prevented by using liquefied `CO_2` alongwith suitable detergent.
However, use of liquefied `CO_2`
with detergent will not be completely safe because detergents also cause pollution, as most of the detergents are nonbiodegradable. Moreover, liquefied `CO_2` will ultimately enter into the atmosphere and add to greenhouse effect.