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Ozone depletion and greenhouse effect

55 questions on Ozone depletion and greenhouse effect from the Environmental Chemistry chapter: 11 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

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In the stratosphere, which step directly produces ozone from atomic oxygen? NEET level
The main role of the stratospheric ozone layer for life on Earth is that it NEET level
Which class of compounds is chiefly responsible for the depletion of the stratospheric ozone layer? NEET level
The 'ozone hole' was first noticed over which region? NEET level
Among the following gases emitted by human activity, the one that makes the largest contribution to the enhanced greenhouse effect, according to the standard NC... NEET level
The Montreal Protocol is an international agreement aimed at NEET level
Greenhouse gases heat the lower atmosphere mainly because they absorb NEET level
Ozone present near the ground level (troposphere) is regarded as NEET level
Increased exposure to ultraviolet-B radiation caused by ozone depletion can lead to NEET level
Nitric oxide released by supersonic jet aircraft flying in the stratosphere can destroy ozone through the reaction NEET level
Which of the following is a proposed replacement for CFCs that contains no chlorine? NEET level
In the chlorine chain, the steps are Cl + O3 -> ClO + O2 and ClO + O -> Cl + O2. The net reaction obtained by adding them is JEE Main level
Polar stratospheric clouds contribute to the Antarctic ozone hole mainly because their ice and acid particle surfaces JEE Main level
The Antarctic ozone loss becomes severe in September-October rather than in the dark midwinter because JEE Main level
Which pair consists of chlorine reservoir species that temporarily hold chlorine in an unreactive form? JEE Main level
Assertion (A): CFCs can destroy stratospheric ozone although they are chemically very unreactive near the ground. Reason (R): Being stable and insoluble, CFCs s... JEE Main level
Match the gas in Column I with its important source in Column II. Column I: (P) CH4, (Q) CO2, (R) N2O, (S) CFC-12. Column II: (1) refrigerants and aerosol prope... JEE Main level
Nitrogen and oxygen make up about 99% of dry air but are not greenhouse gases. The reason is that JEE Main level
HCFC-22 (CHClF2) has a much lower ozone depletion potential than CF2Cl2. The best reason is that JEE Main level
Which statement about hydrofluorocarbons such as CH2FCF3 is correct? JEE Main level
In the nitric oxide cycle, NO + O3 -> NO2 + O2 followed by NO2 + O -> NO + O2, the species that acts as the catalyst is JEE Main level
The ozone layer is described as being in dynamic equilibrium. This means that JEE Main level
An increase in UV-B reaching the ocean surface harms phytoplankton. A direct consequence of reduced phytoplankton is JEE Main level
In the troposphere, the oxygen atoms that lead to ozone in photochemical smog come mainly from JEE Main level
Increasing the concentration of CO2 warms the lower atmosphere because CO2 JEE Main level
In CF2Cl2 the stratospheric photolysis breaks a C-Cl bond and not a C-F bond. Taking C-Cl as about 340 kJ mol^-1 and C-F as about 485 kJ mol^-1, the reason is t... JEE Main level
The Antarctic stratosphere shows far greater ozone loss than the Arctic mainly because JEE Main level
Assertion (A): Although CO2 traps less heat per molecule than a CFC molecule, CO2 is responsible for the larger part of the enhanced greenhouse effect. Reason (... JEE Main level
In the lower stratosphere over Antarctica atomic oxygen is scarce, so the step ClO + O -> Cl + O2 is slow there. The chlorine cycle can still continue through JEE Main level
Which of the following statements about the chlorine-catalysed destruction of ozone (Cl + O3 -> ClO + O2; ClO + O -> Cl + O2) are correct? JEE Main level
Select the species that are greenhouse gases. JEE Main level
Which of the following are consequences of stratospheric ozone depletion? JEE Main level
Atomic masses: C 12, F 19, Cl 35.5; Avogadro constant N_A = 6.02x10^23 mol^-1. Assume each molecule of CF2Cl2 in 24.2 g of the compound loses exactly one Cl ato... JEE Main level
On the surface of polar stratospheric clouds, ClONO2 + H2O -> HOCl + HNO3 is followed by HOCl + HCl -> Cl2 + H2O. Adding the two steps, the overall change and t... JEE Advanced level
A research aircraft measures the lower stratosphere at two places. Region X: ClO is about 1 ppb and ozone is very low. Region Y: ClO is negligible and ozone is ... JEE Advanced level
During Antarctic winter, HNO3 is taken up in polar stratospheric cloud particles and removed from the gas phase. The effect on ozone loss in spring is that JEE Advanced level
A pollutant X forms in sunlight through NO2 -> NO + O followed by O + O2 -> X. At ground level X irritates the lungs and damages crops, while in the stratospher... JEE Advanced level
In the polar lower stratosphere the cycle is: 2Cl + 2O3 -> 2ClO + 2O2; ClO + ClO -> Cl2O2; Cl2O2 -> Cl + ClOO; ClOO -> Cl + O2. The net reaction and the number ... JEE Advanced level
The data below are assumed for this problem: ODP (relative to CFC-11 = 1.00) and 100-year GWP (relative to CO2 = 1). Gas P: ODP 1.00, GWP 4700. Gas Q: ODP 0.05,... JEE Advanced level
Match the reaction in Column I with its role in Column II. Column I: (P) O2 ->[hnu] 2O followed by O + O2 -> O3; (Q) ClONO2 + HCl -> Cl2 + HNO3 on cloud particl... JEE Advanced level
In sunlight, tropospheric ozone builds up in smog through NO2 -> NO + O, O + O2 -> O3 and O3 + NO -> NO2 + O2. These three steps alone do not allow ozone to acc... JEE Advanced level
Which of the following species is a free radical (odd-electron species) taking part directly in the catalytic destruction of stratospheric ozone? JEE Advanced level
On polar stratospheric clouds, 0.35 mol of ClONO2 reacts completely with excess HCl (ClONO2 + HCl -> Cl2 + HNO3), and in spring all the Cl2 formed is photolysed... JEE Advanced level
Each Cl atom in the chain destroys on average 1.0e+05 ozone molecules before being removed. For 2.0e-09 mol of Cl atoms, the mass of ozone destroyed is (use O3 ... JEE Advanced level
Two students discuss CFC-12. Student A: the Cl released arises from the C-F bond. Student B: it arises from the C-Cl bond on absorption of UV in the stratospher... JEE Advanced level
A chain started by a Cl atom propagates through the two steps Cl + O3 -> ClO + O2 and ClO + O -> Cl + O2. The chain ends when Cl reacts with methane, Cl + CH4 -... JEE Advanced level
Which statements about the fate of CFCs are correct? JEE Advanced level
Which statements correctly describe the formation of the Antarctic ozone hole? JEE Advanced level
Which of the following species are free radicals (contain an unpaired electron)? JEE Advanced level
Regarding the replacements for CFCs, which statements are correct? JEE Advanced level
Which statements about ozone in the troposphere are correct? JEE Advanced level
Which statements about the greenhouse effect are correct? JEE Advanced level
Which of the following are expected consequences of global warming? JEE Advanced level
Which of the following are correctly balanced steps of the standard scheme for chlorine-catalysed ozone loss and activation of reservoirs? JEE Advanced level
A UV photon of wavelength 215 nm is used to photolyse O2, whose O=O bond energy is 498 kJ mol^-1. Take h = 6.63x10^-34 J s, c = 3x10^8 m s^-1, N_A = 6.02x10^23 ... JEE Advanced level