The noble gas that does NOT occur in the atmosphere is :

• Ne

• He

• Kr

• Ra

Which one of the following is not a common component of photochemical smog?

• Ozone

• Acrolein

• Peroxyacetyl nitrate

• Peroxyacetyl nitrate

Which one of  the following statements regarding photochemical smog is not correct?

• Carbon monoxide does not play any role in photochemical smog formation

• Photochemical smog is an oxidising agent in character

• Photochemical smog is formed through photochemical reaction involving solar energy

• Photochemical smog is formed through photochemical reaction involving solar energy

Green chemistry means such reactions which 

• produce colour during reactions

• reduce the use and production of hazardous chemicals

• are related to the depletion of the ozone layer

• are related to the depletion of the ozone layer

Which of the following is a sink for CO?

• Haemoglobin

• Micro-organisms present in the soil
  
  

• Oceans

• Oceans

Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity?

• N₂O₅

• NO₂

• NO

• N₂O

Which of the following region is coldest?

• Stratosphere

• Troposphere

• Mesosphere

• Thermosphere

68.

Which of the following statement(s) is not correct?

• Suspended particulate matter is an important pollutant released by diesel vehicles

• Soot particles (size < 5$\mathrm{\mu }$) cause fibrosis of the lung living

• H₂SO₄ particulates have size of 500- 1000 nm

• Photochemical smog is formed by oxides of sulphur, smoke and dust particles

Green chemistry means such reactions which

• produce colour during reactions

• reduce the use and production of hazardous chemicals

• are related to the depletion of ozone layer

• study the reactions in plants

Which one of the following is present as an active ingredient in bleaching powder for bleaching action?

• Ca(OCl)₂

• CaO₂Cl

• CaCl₂

• CaOCl₂