Ozone layer is being depleted. This is due to : from Chemistry N

Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

21.

Which of the following is a favourable factor for cation formation ?

  • Low ionisation potential

  • High electron affinity

  • High electronegativity

  • Small atomic size


22.

Which of the following statements is not an essential feature of an optically active molecule ?

  • It will rotate the plane of polarised light

  • It will have a non-superimposable mirror image

  • It will have no element of symmetry

  • It will have an asymmetric carbon atom


23.

Which one of the following is the most stable reactive intermediate?


24.

The reagent which could distinguish between 1-hexyne and 1-hexene is :

  • Ag(NH3)2+

  • KMnO4

  • Br2 in CCl4

  • H2SO4


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25.

Choose the correct reagent required to carry out the transformation :

  • Zn + conc. HCl

  • conc. H2SO4

  • Li then H2O

  • H2/Pt


26.

Which is maximum hydrated ?

  • NaCl

  • MgCl2

  • AlCl3

  • SiCl4


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27.

Ozone layer is being depleted. This is due to :

  • NO (nitric oxide) emission from supersonic jets

  • chlorofluoro carbon used as aerosols

  • Both (a) and (b)

  • None of the above


A.

NO (nitric oxide) emission from supersonic jets

Main reason of O3 layer depletion is the release of chlorofluorocarbon compounds, called freons and emission of nitric oxide (NO) from supersonic jets

NO + O3  NO2 + O2

CF2ClUV Cl° + C°F2Cl

Cl°O + O3   ClO° + O2

Cl°O + O  Cl° + O2

The chlorine free radicals are continuously regenerated and causes the breakdown of ozone.


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28.

Arrange the following compounds in increasing order of rate of reaction towards nucleophilic substitution :

  • I < II < III

  • I < III < II

  • III < II < I

  • II < III < I


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29.

Which can dissolve I2 ?

  • KI

  • NaI

  • LiI

  • HI


30.

The oxygen carrying pigment , oxyhaemocyanin containing two copper ions is diamagnetic , because :

  • the two copper ions are in + 1oxidation state

  • one copper ion is in + 1oxidation state while other is in + 2 oxidation state

  • of the strong antiferromagnetic interactions between two copper ions

  • of the ferromagnetic interactions between the two copper ions


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