What are X and Y in the following reaction?CF2Cl2 →UV&n

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 Multiple Choice QuestionsMultiple Choice Questions

121.

At T (K), 100 L of dry oxygen is present in a sealed container. It is subjected to silent electric discharge, till the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at T (K) ?

  • 50

  • 60

  • 30

  • 40


122.

Bhopal gas tragedy of 1984 was caused by

  • carbon monoxide

  • phosgene

  • methyl cyanate

  • methyl isocyanate


123.

Among the following compounds, which one is not responsible for depletion of ozone layer?

  • CH4

  • CFCl3

  • NO

  • Cl2


124.

The chemical entities present in thermosphere of the atmosphere are

  • O2+, O+, NO+

  • O3

  • N2, O2, CO2, H2O

  • O3, O2+, O2


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125.

The acceptable level of carbon monoxide gas (CO) in the atmosphere in ppm level is

  • 9

  • 250

  • 49

  • 850


126.

Which air pollutant is responsible for Bhopal gas tragedy?

  • PIC

  • CFC

  • MIC

  • CO


127.

The pair of gases responsible for acid rain are

  • H2, O3

  • CH4, O3

  • NO2, SO2

  • CO, CH4


128.

Cataract and skin cancer are caused by

  • depletion of nitric oxide

  • depletion of ozone layer

  • increase in methane

  • depletion of nitrous oxide


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129.

On the top of mountain, water boils at

  • high temperature

  • same temperature

  • high pressure

  • low temperature


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130.

What are X and Y in the following reaction?

CF2Cl2 UV X + Y

  • CF2Cl, Cl

  • C2F4, Cl2

  • CFCl2, F

  • CCl2, F2


A.

CF2Cl, Cl

Since, chlorofluorocarbon compounds, i.e , freons (CFCs) are non-reactive, non-inflamable, non-toxic organic molecules, these are widely used in air conditioner, refrigerators, in electronic industry for cleaning computer parts. Due to very long life time (CF2Cl2-12 '139 years, CFCl3-11 77 years), these compounds ultimately react the stratosphere where they get broken down by powerful UV radiations and release chlorine free radical. The chlorine free radicals react with ozone and cause its depletion.

     CF2Cl2 hv C·l + C·F2ClCFCl3 hv C·l + C·F2ClHence, x+ y= C·l + C·F2Cl


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