Ozone Depleting Potential (ODP) of any substance/chemical species is defined as the ratio of long-term impact on ozone from the substance/chemical species to the impact from an equivalent amount of _______.

Correct option is B

The Ozone Depleting Potential (ODP) is a metric used to compare the relative ability of various substances to destroy the ozone layer. The ODP of a substance is measured in relation to CFC-11, which is assigned an ODP of 1.
1. Definition of ODP:
· ODP is the ratio of the ozone depletion caused by a unit mass of a substance to the ozone depletion caused by the same mass of CFC-11.
2. Why CFC-11?
· CFC-11 (trichlorofluoromethane) has historically been used as the reference compound because it is one of the most well-studied ozone-depleting substances.
3. Impact of CFC-11:
· It is a chlorofluorocarbon (CFC) that releases chlorine atoms into the stratosphere, causing significant ozone depletion.
4. Other Substances:
· Substances like halons, carbon tetrachloride (CCl4), and other CFCs have varying ODPs measured relative to CFC-11.
Thus, the correct answer is CFC-11.
Information Booster: 1. ODP Scale:
· CFC-11 has an ODP of 1.0 (reference).
· Other CFCs and halons have ODPs ranging from slightly less than 1 to over 10.
2. Examples of ODPs:
· Halon-1301: ODP ≈ 10.
· HCFC-22: ODP ≈ 0.05.
· HFCs: ODP ≈ 0 (non-ozone depleting).
3. Key Impact of ODP Substances:
· Substances with high ODP are regulated under the Montreal Protocol.
4. Montreal Protocol:
· A global treaty designed to phase out the production and use of ozone-depleting substances.