Chemistry miscellaneous


  1. The advantage of detergents over soaps is









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    Soaps are made of materials found in nature. Detergents are synthetic. a big drawback of washing with soap is that the minerals in water react with those in soap, leaving an insoluble film. Detergents react less to minerals in water and for all practical purposes are the product of choice for laundry, unless you have very soft water. On the other hand, soap will combine with the magnesium and calcium ions in hard water to create an insoluble residue that can clog drains and stick to clothing.

    Correct Option: C

    Soaps are made of materials found in nature. Detergents are synthetic. a big drawback of washing with soap is that the minerals in water react with those in soap, leaving an insoluble film. Detergents react less to minerals in water and for all practical purposes are the product of choice for laundry, unless you have very soft water. On the other hand, soap will combine with the magnesium and calcium ions in hard water to create an insoluble residue that can clog drains and stick to clothing.


  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. Formation of ozone hole is maximum over









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    A continent sized hole (thinning) has been formed over Antarctica as a result of damage to ozone. Most ozone is formed in the stratosphere over the equation and spread by winds around the globe. Icy particles in polar stratospheric clouds catalyze the release of chlorine (from CFC) which destroys ozone. The thinning of ozone is maximum because winter there is exceptionally cold.

    Correct Option: C

    A continent sized hole (thinning) has been formed over Antarctica as a result of damage to ozone. Most ozone is formed in the stratosphere over the equation and spread by winds around the globe. Icy particles in polar stratospheric clouds catalyze the release of chlorine (from CFC) which destroys ozone. The thinning of ozone is maximum because winter there is exceptionally cold.


  1. What is the element that is in the highest percentage in the composition of the earth ?









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    Earth, our home, is the third planet from the sun. It is the only planet known to have an atmosphere containing free oxygen, oceans of liquid water on its surface, and, of course, life. Earth is the fifth largest of the planets in the solar system smaller than the four gas giants, Jupiter, Saturn, Uranus and Neptune, but larger than the three other rocky planets, Mercury, Mars and Venus. Roughly 71 percent of Earth’s surface is covered by water, most of it in the oceans. About a fifth of its atmosphere is made up of oxygen, produced by plants.

    Correct Option: B

    Earth, our home, is the third planet from the sun. It is the only planet known to have an atmosphere containing free oxygen, oceans of liquid water on its surface, and, of course, life. Earth is the fifth largest of the planets in the solar system smaller than the four gas giants, Jupiter, Saturn, Uranus and Neptune, but larger than the three other rocky planets, Mercury, Mars and Venus. Roughly 71 percent of Earth’s surface is covered by water, most of it in the oceans. About a fifth of its atmosphere is made up of oxygen, produced by plants.



  1. The most suitable vessel for storing concentrated sulphuric acid is









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    Concentrated Sulfuric acid can only be stored in glass, no metal lids, some plastic containers. It will attack anything organic, causing severe burns, the good thing is it will not start a fire but if it goes into contact with a metal it may generate hydrogen gas, an explosion risk.

    Correct Option: C

    Concentrated Sulfuric acid can only be stored in glass, no metal lids, some plastic containers. It will attack anything organic, causing severe burns, the good thing is it will not start a fire but if it goes into contact with a metal it may generate hydrogen gas, an explosion risk.