Chemistry GK Questions Quiz-4

Chemistry GK Questions Quiz-4

Chemistry Multiple Choice Questions (MCQs) Quiz for State and UPSC Civil Services Examinations. Objective Questions on Chemistry for competitive examinations.

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

    (1) Silicon 
    (2) Oxygen
    (3) Magnesium 
    (4) Iron
    Answer:
    61. (2) 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.


    62. Formation of ozone hole is maximum over

    (1) Africa 
    (2) India
    (3) Antarctica 
    (4) Europe
    Answer:
    62. (3) 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.


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

    (1) increasing the average global temperature in recent years
    (2) higher rate of photosynthesis
    (3) checking the penetration of ultra-violet rays to the earth
    (4) supplying oxygen for people travelling in jets
    Answer:
    63. (3) 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.


    64. The advantage of detergents over soaps is

    (1) Detergents are soluble in water
    (2) Detergents could not give much lather
    (3) Detergents give lather even with hard water
    (4) Soaps give lather with only soft water
    Answer:
    64. (3) 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.


    65. The fundamental particles present in the nucleus of an atom are

    (1) Electron, proton
    (2) Proton, neutron
    (3) Neutron, electron
    (4) Neutron, positron
    Answer:
    65. (2) The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford’s interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The proton–neutron model of nucleus was proposed by Dmitry Ivanenko in 1932. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the orbiting electrons.

    66. Bleaching action of moist sulphur di-oxide is because of its

    (1) basic property
    (2) acidic property
    (3) oxidising property
    (4) reducing property
    Answer:
    66. (3) In moist conditions, sulphur dioxide is a bleaching agent. In the reducing action of SO2, oxygen is removed from coloured dye. Sulphur dioxide is used to bleach wool and silk. Salts of sulphur dioxide are also used in bleaching. Calcium hydrogen sulphite Ca(HSO3)2 is used to whiten wood pulp in the
    manufacturing of paper. Other than SO2, sodium hydrosulphite (Na2S2 O4) is also used to bleach wool.
    However, bleaching using SO2 is not permanent. On exposure to air and light, the original colour slowly returns as oxygen in air oxidises the bleached substance.


    67. The long range potential of nuclear energy in India depends on its reserves of

    (1) thorium 
    (2) uranium
    (3) plutonium 
    (4) radium
    Answer:
    67. (2) India’s domestic uranium reserves are small and the country is dependent on uranium imports to fuel its nuclear power industry. Since early 1990s, Russia has been a major supplier of nuclear fuel to India. Due to dwindling domestic uranium reserves, electricity generation from nuclear power in India
    declined by 12.83% from 2006 to 2008. Large deposits of natural uranium, which promises to be one of the top 20 of the world’s reserves, have been found in the Tummalapalle belt in the southern part of the
    Kadapa basin in Andhra Pradesh in March 2011.


    68. Which of the following gases will effuse out of football bladder most quickly ?

    (1) He 
    (2) H2
    (3) N2 
    (4) O2
    Answer:
    68. (2) Hydrogen is a chemical element with symbol H and atomic number 1. With an average atomic weight of 1.00794 u (1.007825 u for hydrogen-1), hydrogen is the lightest element and its monatomic form (H1) is the most abundant chemical substance, constituting roughly 75% of the Universe’s baryonic mass. Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water molecule and in most organic compounds.


    69. Which of the following alkali metals has highest specific heat?

    (1) Caesium 
    (2) Rubidium
    (3) Potassium 
    (4) Lithium
    Answer:
    69. (4) Lithium has the highest specific heat capacity of any solid element. Because of its specific heat capacity, the highest of all solids, lithium metal is often used in coolants for heat transfer applications. It belongs to the alkali metal group of chemical elements. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable. For this reason, it is typically stored in mineral oil.


    70. In which of the following substances all carbon atoms are quaternary in nature ?

    (1) Graphite 
    (2) Diamond
    (3) Teflon 
    (4) Napthalene
    Answer:
    70. (2) carbon atoms in diamond are quaternary in nature. The crystal structure of a diamond is a face-centered cubic or FCC lattice. Each carbon atom joins four other carbon atoms in regular tetrahedrons (triangular prisms). Based on the cubic form and its highly symmetrical arrangement of atoms, diamond crystals can develop into several different shapes, known as ‘crystal habits’.


    71. Which of the following is a natural dye ?

    (1) Crystal violet
    (2) Aniline blue
    (3) Alizarin
    (4) Phenolphthalein
    Answer:
    71. (3) Alizarin or 1,2-dihydroxyanthraquinone (also known as Mordant Red 11 and Turkey Red is an organic compound with formula C14 H8 O4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural pigment to be duplicated synthetically.Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as Rose madder and Alizarin crimson. Alizarin in the most common usage of the term has a deep red colour, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue.


    72. The ratio of pure gold in 18 carat gold is :

    (1) 60% 
    (2) 75%
    (3) 80% 
    (4) 90%
    Answer:
    72. (2) There are various grades of gold purity, determined by the ratio of their alloy composition and rated by a karat system. Typical karat purities range from 10 karats to 24 karats (pure gold), with a wide variation of usage from country to country. 18 karat gold consists of 75% gold and 25% alloy metals. 18 karat gold has been found to be the perfect balance between gold purity and strength. Brilliance offers a variety of exquisite 18 karat gold jewelry.


    73. Diamond is harder than graphite because of :

    (1) difference in layers of atoms
    (2) tetrahedral structure of diamond
    (3) difference of crystalline structures
    (4) None of these
    Answer:
    73. (1) Diamond is harder than graphite because diamond has a more complex structure. Diamond’s structure is like many pentagons connected together, each pentagon sharing a side with another pentagon or each pentagon sharing a point with another pentagon. All the points are linked together in some way. Graphite’s structure is very loose, with its bonds forming layers. There will be one sheet of elements bonded together, but then another sheet of bonds of elements will lay on top of that, and there will be very weak bonds holding those sheets together.


    74. Gobar gas contains mainly :

    (1) methane 
    (2) ethylene
    (3) propylene 
    (4) acetylene
    Answer:
    74. (1) Bio gas is a clean unpolluted and cheap source of energy in rural areas. It consists of 55-70% methane which is inflammable. Bio gas is produced from cattle dung in a bio gas plant commonly known as gobar gas plant through a process called digestion. It helps in reducing the deforestation as it arrests for cutting of trees for firewood. It also helps in maintaining ecological balance, in rural sanitation and it needs Lower capital cost and almost cost free maintenance.


    75. Which of the following elements is non-radioactive ?

    (1) Uranium 
    (2) Thorium
    (3) Plutonium 
    (4) Zirconium
    Answer:
    75. (4) Zirconium is non-radioactive. It is a chemical element with the symbol Zr, atomic number 40 and atomic mass of 91.224. The name of zirconium is taken from the mineral zircon, the most important source of zirconium. It is a lustrous, grey-white, strong transition metal that resembles titanium. Zirconium is mainly used as a refractory and opacifier, although minor amounts are used as alloying agent for its strong resistance to corrosion.


    76. The gas used for artificial fruit ripening of green fruit is

    (1) Ethylene 
    (2) Acetylene
    (3) Ethane 
    (4) Methane
    Answer:
    76. (1) Ethylene can promote ripening in tomatoes, bananas, citrus, pineapples, dates, persimmons,
    pears, apples, melons, mangos, avocados, papayas and jujubes - a clear indication that the action of
    ethylene is general and widespread amongst a number of fruits. It is clear that ethylene is a ripening hormone - a chemical substance produced by fruits with the specific biological phenomenon of accelerating the normal process of fruit maturation and senescence.


    77. What is the element required for solar energy conversion ?

    (1) Beryllium
    (2) Tantalum
    (3) Silicon
    (4) Ultra pure carbon
    Answer:
    77. (3) The most prevalent bulk material for solar cells is crystalline silicon (abbreviated as a group as c-Si), also known as “solar grade silicon”. Bulk silicon is separated into multiple categories according to crystallinity and crystal size in the resulting ingot, ribbon, or wafer.


    78. Which of the following type of coal has the lowest proportion of volatile matter ?

    (1) Lignite 
    (2) Peat
    (3) Bituminous 
    (4) Anthracite
    Answer:
    78. (4) Anthracite has the lowest proportion of volatile matter. Volatile matter in coal refers to the components of coal, except for moisture, which are liberated at high temperature in the absence of air. This is usually a mixture of short and long chain hydrocarbons, aromatic hydrocarbons and some sulfur. The volatile matter of coal is determined under rigidly controlled standards.


    79. What is the chemical name for ‘Baking Soda’ ?

    (1) Sodium carbonate
    (2) Sodium bicarbonate
    (3) Sodium nitrite
    (4) Sodium nitrate
    Answer:
    79. (2) Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula
    NaHCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite. It is a component of the mineral natron and is found dissolved in many mineral springs.

    80. Saccharin is made up of

    (1) Toluene 
    (2) Phenol
    (3) Propane 
    (4) Butane
    Answer:
    80. (1) Saccharin can be produced in various ways. The original route by Remsen &Fahlberg starts with
    toluene. Saccharin is an artificial sweetener. The basic substance, benzoic sulfilimine, has effectively no food energy and is much sweeter than sucrose, but has a bitter or metallic aftertaste, especially at high
    concentrations. It is used to sweeten products such as drinks, candies, cookies, medicines, and toothpaste.

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