Statement I : Chlorine radicals (Cl) initiate the chain reaction for ozone depletion. Statement I : Gaseous hypo- chlorous acid and chlorine are photolysed by sunlight.

Statement I is true as chlorine radicals (Cl) are the primary agents that initiate the catalytic chain reaction for stratospheric ozone depletion [2]. A single chlorine atom can destroy thousands of ozone molecules by reacting with ozone to form chlorine monoxide (ClO), which then reforms the chlorine radical to repeat the cycle [4]. Statement II is also true and provides the correct explanation for Statement I. In the stratosphere, chlorine is often stored in reservoir species like hypochlorous acid (HOCl) and molecular chlorine (Cl2) [3]. During the polar spring, these species are photolysed by sunlight, releasing active chlorine radicals into the atmosphere [4]. This photolysis process is the critical step that generates the radicals necessary to initiate the ozone destruction cycle described in Statement I [3].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 19: Ozone Depletion > The chemical reaction > p. 268
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Ozonosphere > p. 276
3. [4] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > ozone depletion > p. 13
4. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 19: Ozone Depletion > R9.R.4. Role of polar stratospheric clouds in ozone depletion. > p. 270