Chemistry miscellaneous


  1. The presence of ozone in the stratosphere is responsible for









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    Ozone in the ozone layer filters out sunlight wavelengths from about 200 nm UV rays to 315 nm, with ozone peak absorption at about 250 nm. This ozone UV absorption is important to life, since it extends the absorption of UV by ordinary oxygen and nitrogen in air (which absorbs all wavelengths < 200 nm) through the lower UV-C (200 nm-280 nm) and the entire UV-B band (280 nm-315 nm). The small unabsorbed part that remains of UV-B after passage through ozone causes sunburn in humans, and direct DNA damage in living tissues in both plants and animals.

    Correct Option: C

    Ozone in the ozone layer filters out sunlight wavelengths from about 200 nm UV rays to 315 nm, with ozone peak absorption at about 250 nm. This ozone UV absorption is important to life, since it extends the absorption of UV by ordinary oxygen and nitrogen in air (which absorbs all wavelengths < 200 nm) through the lower UV-C (200 nm-280 nm) and the entire UV-B band (280 nm-315 nm). The small unabsorbed part that remains of UV-B after passage through ozone causes sunburn in humans, and direct DNA damage in living tissues in both plants and animals.


  1. Which of the following is chiefly present in LPG (Liquefied Petroleum Gas) ?









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    Liquid petroleum gas is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. it has primarily butane (C4H10).

    Correct Option: D

    Liquid petroleum gas is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. it has primarily butane (C4H10).



  1. Which of the following is used to iodise common salf ?









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    Iodized salt (also spelled iodised salt) is table salt mixed with a minute amount of various salts of the element iodine. Table salt with iodide salt slowly loses its iodine content through the process of oxidation and iodine evaporation. Edible salt can be iodised by spraying it with a potassium iodate solution. 60 ml of potassium iodate.

    Correct Option: C

    Iodized salt (also spelled iodised salt) is table salt mixed with a minute amount of various salts of the element iodine. Table salt with iodide salt slowly loses its iodine content through the process of oxidation and iodine evaporation. Edible salt can be iodised by spraying it with a potassium iodate solution. 60 ml of potassium iodate.


  1. Milk is a colloidal system in which:









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    A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

    Correct Option: B

    A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.



  1. The enzyme that converts glucose to ethyl alcohol is :









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    The fermentation of sugar into ethanol is one of the earliest biotechnologies employed by humanity. Fermentation of fermentable sugars by suitable yeast produces ethanol (ethyl alcohol). Yeast is a single celled fungus containing a number of enzymes useful during fermentation. Brewers yeast and wine yeast, for example, contain zymase, an enzyme that can convert glucose to ethanol.

    Correct Option: C

    The fermentation of sugar into ethanol is one of the earliest biotechnologies employed by humanity. Fermentation of fermentable sugars by suitable yeast produces ethanol (ethyl alcohol). Yeast is a single celled fungus containing a number of enzymes useful during fermentation. Brewers yeast and wine yeast, for example, contain zymase, an enzyme that can convert glucose to ethanol.