VMMC VMMC Medical Solved Paper-2012

  • question_answer
    Which is always present in photochemical smog?

    A)  \[{{O}_{3}}\]           

    B) \[C{{O}_{2}}\]

    C) \[S{{O}_{2}}\]           

    D) \[C{{H}_{4}}\]

    Correct Answer: A

    Solution :

     Photochemical smog occurs  at high temperature over cities and towns due to stull air, emission of nitrogen oxides and hydrocarbons from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehydes and ketones, nitrogen oxide, oxygen and ketones combines to form Peroxy Acyi Nitrates (PAN), which is responsible for the eye irritation. This smog was first observed in Los Angeles, so called as Los Angeles smog. Classical (London) Smog was reported in 1952 in London. It occurs at low temperature,   contains   sulphur  gases (hydrogen sulphide, sulphur diox.de), smoke and dust particles.


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