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Part 067 – Chemistry Previous Year Questions

Q1. Which one of the following vegetable oils is used in the manufacture of paints?
(a) Palm oil
(b) Sunflower oil
(c) Linseed oil
(d) Cottonseed oil
Ans: (c) Linseed oil and castor oils are used mainly as drying agents in paints and varnishes. Linseed oil is generally used in the manufacture of oil paints, drying oil finish or varnish in wood finishing, as a pigment binder in oil paints, as a plasticizer and in the manufacture of linoleum.

Q2. Acid rain is caused by the pollution of environment by

(a) Carbon monoxide and Carbon dioxide
(b) Ozone and Carbon dioxide
(c) Nitrous oxide and Sulphur dioxide
(d) Carbon dioxide and Nitrogen
Ans: (c) Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.Human activities are the main cause of acid rain.

Q3. Which of the following is not a gaseous air pollutant?

(a) Oxides of nitrogen
(b) Hydrocarbon
(c) Smoke
(d) Oxides of sulphur
Ans: (b) The gaseous air pollutants of primary concern in urban settings include sulfur dioxide, nitrogen dioxide, and carbon monoxide; these are emitted directly into the air from the combustion of fossil fuels.Smoke, a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion, is also a pollutant. Hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.

Q4. At room temperature, the metal that remains liquid is:

(a) Mercury (b) Platinum
(c) Lead (d) Zinc
Ans: (a) Mercury is the only metal that is a liquid at normal temperatures and pressure. At room temperatureand pressure, mercury neither readily share valence electrons with other atoms nor interact with each other to form a structure or lattice to become a solid. Infact, mercury is the only metal that doesn’t form diatomic molecules in the gas phase.

Q5. Which is known as carbolic acid?

(a) Phenol (b) Ethanol
(c) Acetic acid (d) Oxalic acid
Ans: (a) Phenol is also known as carbolic acid. It is an aromatic organic compound with the molecular formula C6H5OH. Phenol and its chemical derivatives are essential for production of polycarbonates, epoxies, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides, and numerous pharmaceutical drugs.

Q6. Atomic explosion is triggered by

(a) thermo nuclear reaction
(b) chemical reaction
(c) controlled chain reaction
(d) uncontrolled chain reaction
Ans: (d) During an uncontrolled nuclear chain reaction such as atomic explosion, a radioactive substance gives off energy at a rate that increases rapidly with time, leading to large amounts of radiation and possibly an explosion. The radioactive decay of one atom triggers the decay of some of its neighbors, in turn setting off other atoms; thus, producing large amounts of energy.

Q7. Which method will be employed to test the hardness of water?

(a) Boiling
(b) Distillation
(c) Formation of lather with soap
(d) None of these
Ans: (c) Soap solution is used to measure the hardness of rain water, temporarily hard water and sea-water. Hard water does not form soap lather. This is because magnesium ions or calcium ions present in hard water react with soap to form calcium stearate or magnesium stearate and thus forms scum.

Q8. J.J. Thomson’s proposed model of action is generally called ………………. model.

(a) Cream and cake
(b) Plum and pudding
(d) Plum and cake
(d) Cream and pudding
Ans: (b) The plum pudding model, one of several scientific models of the atom, was first proposed by J. J. Thomson in 1904 soon after the discovery of the electron, but before the discovery of the atomic nucleus. In this model, atoms were known to consist of negatively charged electrons. The model represented an attempt to consolidate the known properties of atoms at the time.

Q9. Which of the following does the Nucleus of an atom consist of?

(a) Protons and neutrons
(b) Protons and electrons
(c) Electrons
(d) Protons
Ans: (a) The nucleus is the small, dense region consisting of protons and neutrons at the center of an atom. Protons and neutrons are bound together to form a nucleus by the nuclear force. The atomic nucleus was discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.

Q10. Kinetics is the study of:

(a) The rate of chemical reaction
(b) How fast the reactions go
(c) The mechanisms and paths of the molecules take in joining from one reactant to products
(d) All of these are correct
Ans: (d) In chemistry, the study of rates and mechanisms of chemical processes and, of the factors on which they depend, is called kinetics. is the study of how fast chemical reactions occur. It provides evidence for the mechanisms of chemical reactions and studies the most effective way of causing a reaction to occur. It studies reaction mechanisms, examining what path the reactants take in order to become the products, and provides a very detailed picture of which bonds are broken and formed during the course of a reaction.

Q11. Which of the following is the main compound of voter ink?

(a) Silver nitrate
(b) Ammonium Chloride
(c) Silver Chloride
(d) Ammonium Nitrate
Ans: (a) The chemical used in voting inks is silver nitrate. Silver nitrate is preferred because it is soluble in water, and makes an inky black solution. When put on the skin, silver nitrate reacts with the salt present on it to form silver chloride that is insoluble in water, and clings to the skin, making it impossible to wash off with soap and water or even alcohol. Mysore Paints and Varnish Limited in Karnataka is only company in India authorised to produce the indelible ink.

Q12. What is a common name for the substance which irritates lachrymal glands ?

(a) Tear Gas
(b) Laughing Gas
(c) Anaesthetic Gas
(d) Noble Gas
Ans: (a) Lacrimal gland, located under the upper eyelid at the outer cornea of the eye, is responsible for tearing during emotional stimulation or following corneal irritation by a foreign body or chemical substance. Tear gas, also called lacrimator, refers to any of a group of substances that irritate the mucous membranes of the eyes, causing a stinging sensation and tears. It produces severe lacrimation by irritating the conjunctivae.

Q13. What is a Bakelite ?

(a) Solution (b) Acid
(c) Base (d) Polymer
Ans: (d) Bakelite is the commercial name for the polymer obtained by the polymerization of phenol and formaldehyde. It is an early plastic. Plastic (from the Greek “plastikos,” meaning moldable) is the popular term for a variety of synthetic, or manmade, polymers. Bakelite was developed by the Belgian-American chemist Leo Baekeland in New York in 1907.

Q14. What do you understand by the term Espuma ?

(a) Foam (b) Soap
(c) Salt (d) Calcium
Ans: (a) Espuma is a Spanish term for froth or foam, and one that is created specifically with the use of a siphon bottle. Espuma is created mainly with liquid that has air incorporated in it to create froth. This is a specific term, since culinary foams may be attained through other means.

Q15. Limestone is a raw material used by which industry?

(a) Aluminium
(b) Fertilizers
(c) Cement
(d) Petrochemicals
Ans: (c) Limestone is used as a raw-material for the manufacture of quicklime (calcium oxide), slaked lime (calcium hydroxide), cement and mortar. Clay and shale are also used as raw materials for the production of cement.

Q16. Atomic number of an atom gives the number of which of the following ?

(a) electrons
(b) protons
(c) neutrons
(d) neutrons and protons
Ans: (b) Atomic number of a chemical element is the number of protons found in the nucleus of an atom of that element, and therefore identical to the charge number of the nucleus. It determines the place of an element in the periodic table. In an uncharged atom, the atomic number is also equal to the number of electrons.

Q17. Which is the highest quality of hard coal?

(a) Anthracite
(b) Bituminous
(c) Lignite
(d) Peat
Ans: (a) Anthracite is the highest rank of coal. It is the most metamorphosed type of coal, in which the carbon content is between 92.1% and 98%. Anthracite coal generally has the highest heating value per ton on a mineral-matter-free basis. Anthracite is often referred to as hard coal.

Q18. Which of the following is not a commercial source of energy?

(a) Coal (b) Petroleum
(c) Natural Gas (d) Firewood
Ans: (d) Firewood, agricultural waste (straw, etc.) and animals waste (cowdung) are the important components of non-commercial energy. It is generally used in the rural area for domestic purposes— mainly cooking. Coal, petroleum products, natural gas and, electricity are the important components of commercial energy.

Q19. The most abundant metal in the Earth’s crust is

(a) zinc (b) copper
(c) aluminium (d) iron
Ans: (c) The most abundant metal on Earth is aluminum. Aluminum is the third most abundant element in the Earth’s crust, and makes up 8 percent of it by parts per million. The most abundant element in the Earth’s crust is Oxygen followed by Silicon. Both of these are non-metals.

Q20. In which of the following ions, the colour is not due to d-d transition ?

(a) (Ti(H2O)6)3+ (b) CoF6 3–
(c) MnO– 4 (d) (Cu(NH3)4)2+
Ans: (c) The colour of transition-metal compounds is normally associated with d-d transitions. However, some transition metal compounds show intense colour in solution in spite of absence of d-electrons. For example, the orange colour of TiBr4, yellow colour of CrO4 2– , orange colour of Cr2O2– 7, intense red colour of (Fe(SCN)4) and deep purple of MnO4 are not due to d—d transitions. In the case of MnO4 ion, the color is due to charge transfer and not due to d-d transitions.

Q21. Adding Cl2 to benzene in the presence of AlCl3 is an example of :

(a) Elimination reaction
(b) Substitution reaction
(c) None of the options
(d) Addition reaction
Ans: (b) The reaction between benzene and chlorine in the presence of a catalyst such as aluminium chloride gives Chlorobenzene. This reaction is an example of electrophilic substitution reaction since one of the hydrogen atoms on the ring is replaced by a chlorine atom.

Q22. Which one of the following has a maximum tendency to form M3 ion ?

(a) N (b) Bi
(c) P (d) As
Ans: (a) Thee general electronic configuration of group 15 elements (N, P, As, Sb and Bi) is ns2np3. Since Nitrogen has smallest size and greatest electronegativity in the family, it may gain three electrons and attain noble gas configuration, forming nitride N3- ions. The other members show little tendency to form tri-negative M3- ions. Their electronegativity is so low that they would generally form covalent compounds even with highly electropositive elements.

Q23. Copper substances when exposed to air gains a green coating due to the formation of:

(a) CuO
(b) CuCO3 Cu(OH)2
(c) CuSO4
(d) Cu(NO3)2
Ans: (b) When copper is exposed to air, it reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface and gains a green coat. This green substance is basic copper carbonate (CuCO3. Cu (OH)2). The formation of this green coating on the surface of a copper object corrodes it.

Q24. The chief constituent of natural gas is:

(a) Methane (b) Helium
(c) Nitrogen (d) Propane
Ans: (a) Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane (CH4). However, it also includes varying amounts of other higher alkanes (ethane, propane), and a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.

Q25. Which of the following vitamins is generally excreted by human in urine?

(a) Vitamin B (b) Vitamin C
(c) Vitamin D (d) Vitamin E
Ans: (*) More than one option is correct. All of the water-soluble vitamins such as Vitamin C and B vitamins (Thiamin, Riboflavin, Niacin, Pyridoxine, Cyanocobalamin and Pantothenic acid) are generally excreted by the human body through urine if they are in excess. These vitamins are absorbed by the digestive tract into the blood stream, metabolized and then excreted by the kidneys in the urine. Distinctly yellow urine may indicate excessive riboflavin (Vitamin B2) intake.

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