Chemistry GK Questions Quiz-2

Chemistry GK Questions Quiz-2

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

    21. Which of the following is used as a lubricant in heavy machines?

    (1) Bauxite 
    (2) Sulphur
    (3) Phosphorus 
    (4) Graphite
    Answer:
    21. (4) Graphite is used as a lubricant in heavy machines. it is made of carbon atoms arranged in sheets of hexagonal units - looks a lot like chicken-wire. Another sheet forms on top of this and so on. There is no proper connection (in ideal graphite) between the sheets, so they are able to slide freely over each other without breaking any bonds.


    22. The anode in a dry cell consists of

    (1) Copper 
    (2) Zinc
    (3) Cadmium 
    (4) Graphite
    Answer:
    22. (2) A “dry-cell” battery is essentially comprised of a metal electrode or graphite rod (elemental carbon) surrounded by a moist electrolyte paste enclosed in a metal cylinder. The cathode is composed of a form of elemental carbon called graphite, which serves as a solid support for the reduction half-reaction. A thin zinc cylinder serves as the anode and it undergoes oxidation.


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

    (1) Potassium iodide
    (2) Iodine
    (3) Potassium iodate
    (4) Sodium iodide
    Answer:
    23. (3) 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.


    24. Milk is a colloidal system in which:

    (1) Water is dispersed in fat
    (2) Fat is dispersed in water
    (3) Fat and water are dispersed in each other
    (4) Fat is dissolved
    Answer:
    24. (2) 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.

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

    (1) Invertase 
    (2) Maltase
    (3) Zymase 
    (4) Diastase
    Answer:
    25. (3) 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.

    26. Silk fibre chemically is :

    (1) Carbohydrate
    (2) Fat 
    (3) Protein
    (4) Cellulose
    Answer:
    26. (3) Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk is composed mainly of fibroin and produced by certain insect larvae to form cocoons. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyxmorireared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colours.


    27. Who developed Hydrogen Bomb?

    (1) Wernher Von Braun
    (2) J. Robert Oppen Heimer
    (3) Edward Teller
    (4) Samuel Cohen
    Answer:
    27. (3) Portions of the development and history of the hydrogen bomb remain classified. But it is public
    knowledge that its chief architect was Dr. Edward Teller. The first H bomb (or thermonuclear bomb /
    fusion bomb) detonated was on November 1, 1952 in Enewetak in the Marshall Islands. The hydrogen bomb is also called the Teller-Ulam design, after Edward Teller and Stanislaw Ulam who helped in the project too.


    28. When there are two electrons in the same orbital, they have:

    (1) same spin
    (2) opposite spin
    (3) same or opposite spin
    (4) no spin
    Answer:
    28. (2) In the case of two electrons occupying the same orbital, the Pauli principle demands that they have opposite spin. The Pauli Exclusion Principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same quantum state simultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles.


    29. Galvanization is the :

    (1) deposition of zinc on iron
    (2) deposition of tin on iron
    (3) deposition of copper on iron
    (4) deposition of aluminium on iron
    Answer:
    29. (1) Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. The term is derived from the name of Italian scientist Luigi Galvani. Although galvanization can be done with electrochemical and electro-deposition processes, the most common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc.


    30. Fermentation of milk to curd is due to :

    (1) Mycobacterium
    (2) Staphylococcus
    (3) Lactobacillus
    (4) Yeasts
    Answer:
    30. (3) Milk contains a sugar called lactose, a disaccharide (compound sugar) made by the glycosidic bonding between glucose and glactose (monosaccharides). When milk is heated to a temperature of 30-40 degrees centigrade and a small amount of old curd added to it, the lactobacillus in that curd sample gets activated and multiplies. These convert the lactose into lactic acid, which imparts the sour taste to curd.


    31. By which organic compound all the oils are known ?

    (1) Carbohydrate
    (2) Protein
    (3) Hydrocarbon
    (4) Ester
    Answer:
    31. (3) Hydrocarbons are organic compounds containing carbon and hydrogen and found in crude oil and natural gas. Hydrocarbons are formed from the remains of marine animals and plants that lived in shallow inland seas, died, and drifted to the bottom. The term petroleum is used as a common denotation for crude oil (mineral oil) and natural gas, i.e., the hydrocarbons from which various oil and gas products are made.


    32. The atomic number of carbon is 6 and its atomic mass is 12. How many are there protons in the nucleus of carbon ?

    (1) 6 
    (2) 12
    (3) 18 
    (4) Zero
    Answer:
    32. (1) There are six (6) protons in Carbon-12. The 12 refers to the number of protons plus the number of neutrons. There are 6 of each in carbon-12. The number of protons in the nucleus of an atom
    determines an element’s atomic number. The mass number of an element is the total of number of
    neutrons and number of protons.


    33. Who developed atom bomb ?

    (1) Warner Wan Brown
    (2) J. Robert Openheimer
    (3) Edward Taylor
    (4) Samuel Koehen
    Answer:
    33. (2) J. (Julius) Robert Oppenheimer was born in New York City on April 22, 1904. Under Oppenheimer’s guidance, the laboratories at Los Alamos were constructed. There, he brought the best minds in physics to work on the problem of creating an atomic bomb. In the end, he was managing more than 3,000 people, as well as tackling theoretical and mechanical problems that arose. He is often referred to as the “father” of the atomic bomb.


    34. The major harmful gas emitted by automobile vehicle which causes air pollution is

    (1) Carbon Monoxide
    (2) Methane
    (3) Carbon dioxide
    (4) Ozone gas
    Answer:
    34. (3) The main gas released from car exhausts — carbon dioxide – is one of the major green house gasses. With large amounts of carbon dioxide being emitted into the atmosphere every day, the carbon cycle goes out of balance, and the carbon dioxide gas remains in the earth’s atmosphere, trapping heat and contributing to global warming and climate change.


    35. The acid used in lead storage cells is

    (1) phosphoric acid
    (2) hydrochloric acid
    (3) nitric acid
    (4) sulphuric acid
    Answer:
    35. (4) Dilute sulfuric acid {H2SO4} serves as the electrolyte in a lead storage battery. The electrodes of the cells in a lead storage battery consist of lead grids. The openings of the anodic grid is filled with spongy (porous) lead. The openings of the cathodic grid is filled with lead dioxide {PbO2}.


    36. Milk tastes sour when kept in the open for sometime due to the formation of

    (1) lactic acid 
    (2) citric acid
    (3) acetic acid 
    (4) carbonic acid
    Answer:
    36. (1) Like many other things, milk contains bacteria, Milk also naturally contains a kind of sugar known as “lactose.” The bacteria that live in milk get energy from this special sugar and use it to reproduce to make even more bacteria. When the bacteria use the lactose sugars to reproduce, they change it from “lactose sugar” into “lactic acid,” which tastes sour.


    37. What is the most commonly used substance in fluorescent tubes?

    (1) Sodium oxide and argon
    (2) Sodium vapour and neon
    (3) Mercury vapour and argon
    (4) Mercury oxide and neon
    Answer:
    37. (3) A fluorescent lamp or fluorescent tube is a gasdischarge lamp that uses electricity to excite mercury vapour. it contains mercury vapour and argon. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp.

    38. What is “milk of magnesia” chemically ?

    (1) Magnesium carbonate
    (2) Sodium bicarbonate
    (3) Calcium hydroxide
    (4) Magnesium hydroxide
    Answer:
    38. (4) Magnesium hydroxide is an inorganic compound with the chemical formula Mg (OH)2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite. Magnesium hydroxide is a common component of antacids and laxatives; it interferes with the absorption of folic acid and iron. Magnesium hydroxide has low solubility in water, with a Ksp of 1.5×10–11; however all of the magnesium hydroxide that does dissolve dissociates.


    39. Soap is prepared by boiling caustic soda with

    (1) Alcohol 
    (2) Kerosene oil
    (3) Glycerine 
    (4) Fats
    Answer:
    39. (4) The most basic kind of soap is made from caustic soda and animal fat. The two are heated together, and then cooled. The process is called “saponification”. In technical terms, saponification involves base (usually caustic soda NaOH) hydrolysis of triglycerides, which are esters of fatty acids, to form the sodium salt of a carboxylate.

    40. Bronze is an alloy of

    (1) Copper and Zinc
    (2) Tin and Zinc
    (3) Copper and Tin
    (4) Iron and Zinc
    Answer:
    40. (3) Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and tough, and it was particularly significant in antiquity, so much that the Bronze Age was named after the metal. However, historical pieces were often made interchangeably of bronzes or brasses with different compositions, so modern museum and scholarly descriptions of older objects increasingly use the more inclusive term “copper alloy” instead. Historically the term latten was used for such alloys.


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