Chemistry GK Questions Quiz-35

Chemistry GK Questions Quiz-35

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

    681. White phosphorus is generally kept under

    (1) Alcohol
    (2) Water
    (3) Glycerine 
    (4) Kerosene oil
    Answer:
    681. (2) White phosphorous is kept under water because it reacts with oxygen but not water. Besides, it is insoluble in water. It presents a significant fire hazard due to its extreme reactivity with atmospheric
    oxygen.

    682. The wire of flash bulbs is made up of

    (1) Mg 
    (2) Ba
    (3) Cu 
    (4) Ag
    Answer:
    682. (1) The wire of flash bulbs is made up of magnesium. Magnesium filaments are contained in bulbs filled with oxygen gas, and electrically ignited by a contact in the camera shutter.

    683. For a spontaneous process

    (1) DG is +ve
    (2) DG is –ve
    (3) DG is equal to zero
    (4) DH is –ve
    Answer:
    683. (2) When DG < 0, a process is spontaneous, when DG = 0 the system is at equilibrium, and DG > 0 has the reverse direction spontaneous. G is a form of energy that tends to reach a minimum for any spontaneous process at constant T and P When DG < 0 (spontaneous processes), DG is equal to the maximum work that can be obtained from the process.

    684. Which of the following has the highest penetrating power?

    (1) a-ray 
    (2) b-ray
    (3) g-ray 
    (4) d-ray
    Answer:
    684. (3) The penetrating power is inversely related to size. Alpha particles, being the largest, penetrate the least. Gamma rays are the most penetrating of the radiations. They are highly energetic waves and are poor at ionising other atoms or molecules.

    685. When cathode rays strike a target of high atomic weight, they give rise to

    (1) a -rays 
    (2) b and g rays
    (3) X-rays 
    (4) positive rays
    Answer:
    685. (3) When cathode rays strike a solid target of high atomic weight and high melting point such as tungsten, molybdenum, etc, they give rise to a highly penetrating radiation called the X-rays (LIT Physics by Dr. P.K Agarwal).

    686. The major use of sulphur is in the manufacture of

    (1) H2SO4 
    (2) H2S
    (3) SO2 
    (4) Fungicide
    Answer:
    686. (1) The major use of sulphur is in the manufacture of sulphuric acid (H2SO4) which is one of the most important compounds made by the chemical industry. It is used to make, literally, hundreds of compounds needed by almost every industry.

    687. Atoms of different elements have

    (1) same atomic number and same electronic configuration
    (2) different atomic number and same eletronic configu-ration
    (3) different atomic number and different number of valence electrons
    (4) same number of electrons and neutrons
    Answer:
    687. (3) Each element’s atoms have a different number of protons, neutrons, and electrons, which is why they have different atomic numbers, difference in valence electrons and other properties. Their reactivity also varies because of the number and activeness of the electrons in the atom.

    688. Organic compounds are

    (1) Covalent compounds
    (2) Ionic compounds
    (3) Co-ordination compounds
    (4) Interstitial compounds
    Answer:
    688. (1) Organic compounds are always covalent compounds because it is more energetically favorable for carbon to covalently bond. Organic compounds, such as carbohydrates, lipids, proteins and nucleic acids, are all examples of covalent compounds.

    689. Which one of the following elements exhibits the greatest tendency to lose electrons ?

    (1) Fluorine 
    (2) Lithium
    (3) Oxygen 
    (4) Zinc
    Answer:
    689. (2) Alkali metals such as Lithium are the most electropositive elements in the periodic table. As alkali metals have low ionization energies, they have a great tendency to lose electrons forming uni-positive ions.

    690. Poison used for killing rats is

    (1) Calcium phosphide (Ca3P2)
    (2) Zinc phosphide (Zn3P2)
    (3) Magnesium nitride (Mg3N2)
    (4) Magnesium phosphide (Mg3P2)
    Answer:
    690. (2) Zinc phosphide is an inorganic compound that is used in pesticide products as a rodenticide. Formulated as attractive bait, it releases phosphine gas once it is exposed to acid and moisture in the stomach. The phosphine gas is very toxic to all animals.

    691. Antacid tablets consist of

    (1) Hydroxides of sodium, magnesium and aluminium
    (2) Hydroxides of magnesium and aluminium
    (3) Hydroxides of sodium and aluminium
    (4) Hydroxides of magnesium and sodium
    Answer:
    691. (2) An antacid is a base which neutralizes stomach acidity. The most common of these bases are hydroxides, carbonates, or bicarbonates such as Aluminum hydroxide, Calcium carbonate, Magnesium carbonate, Magnesium hydroxide, and Sodium bicarbonate.

    692. The element absorbed both in cation and anion form is

    (1) Sulphur 
    (2) Nitrogen
    (3) Calcium 
    (4) Phosphorus
    Answer:
    692. (2) Nitrogen, required in large quantities for healthy plant growth, is supplied either as a cation (ammonium - NH4+ ) or an anion (nitrate - NO3– ). The ratio of these two forms of nitrogen in the nutrient solution can have large effects on both the rate and direction of pH changes with time.

    693. Nucleons are regarded as composites sub-particles known as

    (1) Mesons 
    (2) Quarks
    (3) Leptons 
    (4) Photons
    Answer:
    693. (2)In quantum chromodynamics, nucleons are regarded as composites of three quarks (elementary particles) and pions are composites of two quarks. According to EOB’s rules, nucleons move as fermions while pions move as bosons.

    694. Which of the following is not a greenhouse gas ?

    (1) Water vapour
    (2) O2
    (3) O3 
    (4) CO2
    Answer:
    694. (2)Greenhouse gases are those that can absorb and emit infrared radiation, but not radiation in or near the visible spectrum. The most abundant greenhouse gases in Earth’s atmosphere are: Water vapor (H2O), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Ozone (O3) andCFCs.

    695. Interveinal necrotic spots on leaves appear due to

    (1) HF injury 
    (2) SO2 injury
    (3) NO2injury 
    (4) O3 injury
    Answer:
    695. (2)Injury caused by sulphur oxides show interveinal necrotic areas that are light tan to white. Uninjured tissue next to the veins remains green.

    696. The pollutant responsible for ozone holes is _____.

    (1) CO2 
    (2) SO2
    (3) CO 
    (4) CFC
    Answer:
    696. (4) Chlorofluorocarbons (CFCs) have been held responsible for the depletion of ozone layer. The manufacture of CFCs has been phased out under the Montreal Protocol, and they are being replaced with other products such as HFCs.

    697. The alkoloid naturally found in coffee, cocoa and cola nut is

    (1) Cocaine 
    (2) Morphine
    (3) Tannin 
    (4) Caffeine
    Answer:
    697. (4) Caffeine (C8H10N4O2) is a bitter alkaloid found especially in coffee, tea, cacao, and kola nuts. It is used medicinally as a stimulant and diuretic.

    698. The metal used for making aircrafts and rockets is

    (1) Lead 
    (2) Aluminium
    (3) Nickel 
    (4) Copper
    Answer:
    698. (3) Nickel-based super alloys are an unusual class of metallic materials with an exceptional combination of high temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environment. These materials are widely used in aircraft and power-generation turbines, rocket engines, etc.

    699. The process of improving the quality of rubber by heating it with sulphur is called.

    (1) Vulcanization
    (2) Acceleration
    (3) Sulphonation
    (4) Galvanization
    Answer:
    699. (1) Vulcanization is a chemical process for converting natural rubber into more durable materials via the addition of sulfur or other equivalent curatives or accelerators. These additives modify the polymer by forming cross-links (bridges) between individual polymer chains.

    700. Which of the following is not a noble gas ?

    (1) Hydrogen 
    (2) Helium
    (3) Neon 
    (4) Argon
    Answer:
    700. (1) The noble gases are the chemical elements in group 18 of the periodic table. This chemical series contains helium, neon, argon, krypton, xenon, and radon.


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