General Science – Chemistry MCQs
Q 1.Which among the following are constituents of Brass?
Answer: Correct Answer:A [Zinc and Copper ]
Notes: Brass is an alloy of Copper and Zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. The proportions of Zinc and Copper can vary to create different types of brass alloys with varying mechanical and electrical properties.
Notes: Brass is an alloy of Copper and Zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. The proportions of Zinc and Copper can vary to create different types of brass alloys with varying mechanical and electrical properties.
Q 2.When Sulphur is heated with rubber, the process is commonly known as ?
Answer: Correct Answer:C [Vulcanization]
Notes: Natural rubber becomes soft at high temperature (>335 K) and brittle at low temperatures (<283 k) and shows high water absorption capacity. It is soluble in non-polar solvents and is non-resistant to attack by oxidising agents. To improve upon these physical properties, a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.In the manufacture of tyre rubber, 5% of sulphur is used as a crosslinking agent
Notes: Natural rubber becomes soft at high temperature (>335 K) and brittle at low temperatures (<283 k) and shows high water absorption capacity. It is soluble in non-polar solvents and is non-resistant to attack by oxidising agents. To improve upon these physical properties, a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.In the manufacture of tyre rubber, 5% of sulphur is used as a crosslinking agent
Q 3.What is the electrical state of a molecule, considered the smallest part of matter retaining the properties of the original matter?
Answer: Correct Answer:D [Neutral]
Notes: A molecule represents the smallest portion of a substance that retains the characteristics of the substance. It’s electrically neutral because it’s made up of atoms that bond together, sharing or exchanging electrons to achieve stability. This process balances out the electrical charges of the protons and electrons, rendering the molecule as a whole electrically neutral.
Notes: A molecule represents the smallest portion of a substance that retains the characteristics of the substance. It’s electrically neutral because it’s made up of atoms that bond together, sharing or exchanging electrons to achieve stability. This process balances out the electrical charges of the protons and electrons, rendering the molecule as a whole electrically neutral.
Q 4.What type of fiber is Rayon considered?
Answer: Correct Answer:C [A semi-synthetic fiber]
Notes: Rayon is considered a semi-synthetic fiber. It is made by regenerating natural materials into a usable form. Rayon fibers are derived from cellulose obtained from wood or related agricultural products. It was first commercially produced in 1905 by the Swiss firm J. R. Geigy, originally under the name “artificial silk”
Notes: Rayon is considered a semi-synthetic fiber. It is made by regenerating natural materials into a usable form. Rayon fibers are derived from cellulose obtained from wood or related agricultural products. It was first commercially produced in 1905 by the Swiss firm J. R. Geigy, originally under the name “artificial silk”
Q 5.Mizoroki-Heck reaction is catalyzed by which of the following metals?
Answer: Correct Answer:C [Palladium]
Notes: The Mizoroki-Heck reaction is a cross-coupling reaction that typically involves the coupling of aryl halides with alkenes. It is primarily catalyzed by palladium (Pd) complexes. Palladium is favored due to its ability to facilitate the oxidative addition and reductive elimination steps essential for the reaction. Rhodium, while also a transition metal, is less commonly used for this specific reaction. The Mizoroki-Heck reaction is important in organic synthesis for forming carbon-carbon bonds and is widely utilized in pharmaceuticals and materials science.
Notes: The Mizoroki-Heck reaction is a cross-coupling reaction that typically involves the coupling of aryl halides with alkenes. It is primarily catalyzed by palladium (Pd) complexes. Palladium is favored due to its ability to facilitate the oxidative addition and reductive elimination steps essential for the reaction. Rhodium, while also a transition metal, is less commonly used for this specific reaction. The Mizoroki-Heck reaction is important in organic synthesis for forming carbon-carbon bonds and is widely utilized in pharmaceuticals and materials science.
Q 6.Aluminum is getting popular worldwide today as a “Green Metal”. Which among the following properties of Aluminum makes it a Green Metal?
Answer: Correct Answer:C [Aluminum has fairly high rate of recycling and it can be re-used repeatedly without its quality deteriorating]
Notes: Aluminum is considered a “Green Metal” primarily due to its high recycling rate. Approximately 75% of all aluminum ever produced is still in use today, as it can be recycled indefinitely without losing quality. This process saves energy—recycling aluminum uses about 95% less energy than producing new aluminum from bauxite ore. Additionally, recycling reduces greenhouse gas emissions and conserves natural resources, making aluminum a sustainable choice in various applications.
Notes: Aluminum is considered a “Green Metal” primarily due to its high recycling rate. Approximately 75% of all aluminum ever produced is still in use today, as it can be recycled indefinitely without losing quality. This process saves energy—recycling aluminum uses about 95% less energy than producing new aluminum from bauxite ore. Additionally, recycling reduces greenhouse gas emissions and conserves natural resources, making aluminum a sustainable choice in various applications.
Q 7.Copper is mainly found in the form of Sulfide deposits, Carbonate deposits and Silicate deposits. Which among the following is the correct set of the copper ores in the same order respectively?
Answer: Correct Answer:A [Chalcopyrite, Azurite, Dioptase]
Notes: The correct set of copper ores in the same order of Sulfide deposits, Carbonate deposits, and Silicate deposits is:[A] Chalcopyrite, Azurite, DioptaseSo, option [A] is the correct answer.
Notes: The correct set of copper ores in the same order of Sulfide deposits, Carbonate deposits, and Silicate deposits is:[A] Chalcopyrite, Azurite, DioptaseSo, option [A] is the correct answer.
Q 8.Which of the following is correct about the atomic and ionic radii of the alkaline earth metals?
Answer: Correct Answer:A [it is smaller than corresponding alkali metals in the same periods]
Notes: The atomic and ionic radii of the alkaline earth metals are smaller than corresponding alkali metals in the same periods due to the increased nuclear charge in these elements.
Notes: The atomic and ionic radii of the alkaline earth metals are smaller than corresponding alkali metals in the same periods due to the increased nuclear charge in these elements.
Q 9.Which of the following are the uses of Calcium carbonate?
Answer: Correct Answer:D [All of the above]
Notes: Calcium carbonate is used as a building material in the form of marble and in the manufacture of quick lime. Calcium carbonate is also used in the manufacture of high quality paper. It finds its use as an antacid, mild abrasive in tooth paste, a constituent of chewing gum, and a filler in cosmetics.
Notes: Calcium carbonate is used as a building material in the form of marble and in the manufacture of quick lime. Calcium carbonate is also used in the manufacture of high quality paper. It finds its use as an antacid, mild abrasive in tooth paste, a constituent of chewing gum, and a filler in cosmetics.
Q 10.Which among the following is most advantageous in storage in fuel cells used in small, portable electronics such as phones and laptop computers?
Answer: Correct Answer:C [Formic Acid]
Notes: The cells are called Direct-formic acid fuel cells, in which formic acid is directly fed in the cells. Storage of formic acid is much easier and safer than that of hydrogen because it does not need to be done at high pressures and (or) low temperatures, as formic acid is a liquid at standard temperature and pressure. Formic acid does not cross over the polymer membrane, so its efficiency can be higher than that of methanol. Use of acetic acid in cells does not arise.
Notes: The cells are called Direct-formic acid fuel cells, in which formic acid is directly fed in the cells. Storage of formic acid is much easier and safer than that of hydrogen because it does not need to be done at high pressures and (or) low temperatures, as formic acid is a liquid at standard temperature and pressure. Formic acid does not cross over the polymer membrane, so its efficiency can be higher than that of methanol. Use of acetic acid in cells does not arise.
Q 11.Which of the following is incorrect statement about various ores?
Answer: Correct Answer:D [Flourspar is an ore of Potassium]
Notes: Fluorite or Fluorspar is an ore of Calcium. It is a mineral composed of calcium fluoride. It belongs to the family of halide minerals.
Notes: Fluorite or Fluorspar is an ore of Calcium. It is a mineral composed of calcium fluoride. It belongs to the family of halide minerals.
Q 12.What is the sum of powers of the concentration of the reactants called as?
Answer: Correct Answer:A [Order of reaction]
Notes: The sum of powers of the concentration of the reactants in the rate law expression is known as the order of that chemical reaction.
Notes: The sum of powers of the concentration of the reactants in the rate law expression is known as the order of that chemical reaction.
Q 13.Choose the correct order in terms of Metallic character of these elements?
Answer: Correct Answer:A [Na> Mg >Be > P]
Notes: The correct order would be Na> Mg >Be > P. Metallic character increases down a group and decreases along a period as we move from left to right.
Notes: The correct order would be Na> Mg >Be > P. Metallic character increases down a group and decreases along a period as we move from left to right.
Q 14.Which of the following molecules have a T-shape arrangement?
Answer: Correct Answer:C [Chlorine Trifluoride]
Notes: Chlorine trifluoride has 10 electrons around the central chlorine atom. There are five electron pairs arranged in a trigonal bipyramidal shape and two equatorial lone pairs making the final structure T-shaped.
Notes: Chlorine trifluoride has 10 electrons around the central chlorine atom. There are five electron pairs arranged in a trigonal bipyramidal shape and two equatorial lone pairs making the final structure T-shaped.
Q 15.What is the Gibbs energy of a cell (nF=amount of charge passed, E= EMF of the cell)?
Answer: Correct Answer:C [-nFE]
Notes: If the emf of the cell is E and nF is the amount of charge passed and ∆rG is the Gibbs energy of the reaction, then Gibbs energy is equal to – nFE.
Notes: If the emf of the cell is E and nF is the amount of charge passed and ∆rG is the Gibbs energy of the reaction, then Gibbs energy is equal to – nFE.
Q 16.Which of the following is the product of the reaction between Ethanoic acid and Sodium hydrogen carbonate?
Answer: Correct Answer:B [Sodium acetate]
Notes: Sodium acetate is produced when Ethanoic acid and Sodium hydrogen carbonate reacts with each other. Ethanoic acid reacts with carbonates and hydrogen carbonates to give rise to a salt, carbon dioxide and water.
Notes: Sodium acetate is produced when Ethanoic acid and Sodium hydrogen carbonate reacts with each other. Ethanoic acid reacts with carbonates and hydrogen carbonates to give rise to a salt, carbon dioxide and water.
Q 17.Which part of the soap dissolves in water?
Answer: Correct Answer:A [ionic end]
Notes: The ionic-end of soap dissolves in water while the carbon chain dissolves in oil. The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule.
Notes: The ionic-end of soap dissolves in water while the carbon chain dissolves in oil. The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule.
Q 18.What is the use of iodoform?
Answer: Correct Answer:C [ It is used as an antiseptic for wounds]
Notes: Iodoform is used as an antiseptic for wounds. Iodoform is also known as tri-iodomethane, carbon triiodide, and methyl triiodide. It is also used as a disinfectant.
Notes: Iodoform is used as an antiseptic for wounds. Iodoform is also known as tri-iodomethane, carbon triiodide, and methyl triiodide. It is also used as a disinfectant.
Q 19.Which of the following would come in use to treat diseased skin surfaces?
Answer: Correct Answer:B [ Antiseptics]
Notes: Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces. Examples of antiseptics are furacine, soframicine, etc
Notes: Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces. Examples of antiseptics are furacine, soframicine, etc
Q 20.Which of the following gases is heavier than oxygen?
Answer: Correct Answer:D [Carbon dioxide]
Notes: Carbon dioxide has one carbon atom and two oxygen atoms, and a molecular weight of 44 grams per mole. The oxygen in the air is actually O2, or molecular oxygen, with a molecular weight of 32. Hence, carbon dioxide has a higher density, or is heavier than oxygen.
Notes: Carbon dioxide has one carbon atom and two oxygen atoms, and a molecular weight of 44 grams per mole. The oxygen in the air is actually O2, or molecular oxygen, with a molecular weight of 32. Hence, carbon dioxide has a higher density, or is heavier than oxygen.
Q 21.Which of the following metals is a bad conductor of heat?
Answer: Correct Answer:C [Lead]
Notes: Lead and mercury are metals which are poor conductor of heat unlike all other the metals which are good conductor of heat.
Notes: Lead and mercury are metals which are poor conductor of heat unlike all other the metals which are good conductor of heat.
Q 22.Which of the following is dry ice?
Answer: Correct Answer:D [Solid Carbon dioxide]
Notes: Dry ice is the solid form of carbon dioxide. It is used primarily as a cooling agent. As a gas, CO2 exists naturally in our environment. It’s called “dry ice” because it does not melt.
Notes: Dry ice is the solid form of carbon dioxide. It is used primarily as a cooling agent. As a gas, CO2 exists naturally in our environment. It’s called “dry ice” because it does not melt.
Q 23.Who discovered Sodium?
Answer: Correct Answer:B [Humphry Davy]
Notes: Sodium was first isolated in 1807 by Sir Humphry Davy, who made it by the electrolysis of very dry molten sodium hydroxide, NaOH. Sodium collected at the cathode.
Notes: Sodium was first isolated in 1807 by Sir Humphry Davy, who made it by the electrolysis of very dry molten sodium hydroxide, NaOH. Sodium collected at the cathode.
Q 24.Which of the following can be measured by Hygrometer?
Answer: Correct Answer:B [Relative humidity of atmosphere]
Notes: A hygrometer is also known as a psychrometer. It is a device that is used to measure the humidity in the air. A common way these devices work is by using a material that attracts moisture, and that changes depending on how moist it is.
Notes: A hygrometer is also known as a psychrometer. It is a device that is used to measure the humidity in the air. A common way these devices work is by using a material that attracts moisture, and that changes depending on how moist it is.
Q 25.Match the following:A. Argentite1. CopperB. Bauxite2. IronC. Haematite3. AluminiumD. Cuprite4. SilverA B C D
Answer: Correct Answer:A [4 3 2 1]
Notes: • Silver is extracted from the ore-argentite. The process of extraction of silver is called as cyanide process as sodium cyanide solution is used.• Bauxite is primarily comprised of aluminum oxide compounds.• Haematite ore is mined as the main ore of iron.• Cuprite is an oxide mineral composed of copper oxide Cu2O, and is a minor ore of copper.
Notes: • Silver is extracted from the ore-argentite. The process of extraction of silver is called as cyanide process as sodium cyanide solution is used.• Bauxite is primarily comprised of aluminum oxide compounds.• Haematite ore is mined as the main ore of iron.• Cuprite is an oxide mineral composed of copper oxide Cu2O, and is a minor ore of copper.
Q 26.Which one of the following is an element?
Answer: Correct Answer:D [Diamond]
Notes: Diamond is pure elemental carbon, compressed to its crystal form, under extreme heat and pressure deep within the Earth. The symbol for carbon is C.
Notes: Diamond is pure elemental carbon, compressed to its crystal form, under extreme heat and pressure deep within the Earth. The symbol for carbon is C.
Q 27.Which of the following is the working principle of a washing machine?
Answer: Correct Answer:A [Centrifugation]
Notes: The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifugal force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes.
Notes: The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifugal force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes.
Q 28.Consider the following statements:1. Baking soda is used in fire extinguishers.2. Quicklime is used in the manufacture of glass.3. Gypsum is used in the manufacture of Plaster of Paris.Which of the statements given above is/are correct?
Answer: Correct Answer:D [1, 2 and 3]
Notes: Baking soda is a great as a fire extinguisher for electrical fires and grease fires. When baking soda is heated it releases carbon dioxide and produces water2NaHCO3 – H2O + CO2 + Na2CO3Since carbon dioxide is heavier than air and does not support combustion like oxygen does, it smothers the fire while water that is formed cools the fire to below ignition temperature. Calcium oxide, chemical compound, CaO is also called lime, quicklime, or caustic lime. Calcium oxide is widely used in making porcelain and glass. Plaster of Paris is a type of building material based on calcium sulphate hemihydrate nominally CaSO4.1/ 2H2O.It is created by heating gypsum to about 300°F (150ºC).2CaSO4.2H2O – 2CaSO4.1/ 2H2O + 3H2O
Notes: Baking soda is a great as a fire extinguisher for electrical fires and grease fires. When baking soda is heated it releases carbon dioxide and produces water2NaHCO3 – H2O + CO2 + Na2CO3Since carbon dioxide is heavier than air and does not support combustion like oxygen does, it smothers the fire while water that is formed cools the fire to below ignition temperature. Calcium oxide, chemical compound, CaO is also called lime, quicklime, or caustic lime. Calcium oxide is widely used in making porcelain and glass. Plaster of Paris is a type of building material based on calcium sulphate hemihydrate nominally CaSO4.1/ 2H2O.It is created by heating gypsum to about 300°F (150ºC).2CaSO4.2H2O – 2CaSO4.1/ 2H2O + 3H2O
Q 29.Who recognized and named Oxygen?
Answer: Correct Answer:A [Antoine Lavoisier]
Notes: In 1778, Antoine Lavoisier, considered “The father of modern chemistry”, recognized and named oxygen, and recognized its importance and role in combustion. Antoine Lavoisier discovered the relationship between oxygen and metal that leads to rust. He also proved the role of oxygen in respiration and discovered the chemical composition of water and air. Henry Cavendish discovered hydrogen in 1766 as a colorless, odorless gas that burns and can form an explosive mixture with air.
Notes: In 1778, Antoine Lavoisier, considered “The father of modern chemistry”, recognized and named oxygen, and recognized its importance and role in combustion. Antoine Lavoisier discovered the relationship between oxygen and metal that leads to rust. He also proved the role of oxygen in respiration and discovered the chemical composition of water and air. Henry Cavendish discovered hydrogen in 1766 as a colorless, odorless gas that burns and can form an explosive mixture with air.
Q 30.A tripositive ion has protons whose mass is equal to 23881 times that of an electron. What is the atomic number of that ion?
Answer: Correct Answer:C [13]
Notes: Mass of a proton is 1837 times than that of an electron. Number of protons =23881 /1837= 13
Notes: Mass of a proton is 1837 times than that of an electron. Number of protons =23881 /1837= 13
Q 31.Which of the following is the working principle of a washing machine?
Answer: Correct Answer:A [Centrifugation]
Notes: The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifugal force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes.
Notes: The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifugal force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes.
Q 32.Rosalind Franklin contributed into which of the following major breakthroughs of science?
Answer: Correct Answer:C [Discovery of DNA Double Helix]
Notes: Rosalind Franklin (1920 – 1958) was an English chemist and physicist who contributed to the discovery of the DNA double helix. Her X-ray diffraction image of DNA played an important role in its discovery. She also performed important research into the polio and TMV viruses.
Notes: Rosalind Franklin (1920 – 1958) was an English chemist and physicist who contributed to the discovery of the DNA double helix. Her X-ray diffraction image of DNA played an important role in its discovery. She also performed important research into the polio and TMV viruses.
Q 33.Why a milkman adds a very small amount of baking soda to fresh milk?
Answer: Correct Answer:B [To increase its pH slightly]
Notes: The pH of fresh milk is 6, to set it as curd needs the pH below 6. In order to avoid this, the milkman shifts the pH of fresh milk from 6 to slightly alkaline by adding baking soda. Since, the milk is slightly basic than usual milk, acids produced to set the curd are neutralized by the base added. Therefore, it takes longer time for the curd to set.
Notes: The pH of fresh milk is 6, to set it as curd needs the pH below 6. In order to avoid this, the milkman shifts the pH of fresh milk from 6 to slightly alkaline by adding baking soda. Since, the milk is slightly basic than usual milk, acids produced to set the curd are neutralized by the base added. Therefore, it takes longer time for the curd to set.
Q 34.Which of the following salts has no water of crystallization?
Answer: Correct Answer:D [Baking Soda]
Notes: Baking soda is chemically sodium bicarbonate (NaHCO3) which does not contain any water of crystallization.
Notes: Baking soda is chemically sodium bicarbonate (NaHCO3) which does not contain any water of crystallization.
Q 35.Which among the following is also called as muriatic acid?
Answer: Correct Answer:A [Hydrochloric acid]
Notes: Hydrochloric acid is also called as muriatic acid as many European chemists considered it as salt acid and muriatic refers to brine/salt.
Notes: Hydrochloric acid is also called as muriatic acid as many European chemists considered it as salt acid and muriatic refers to brine/salt.
Q 36.Atoms having the same number of protons but different number of neutrons are called:
Answer: Correct Answer:A [Isotopes]
Notes: Atoms that have the same number of protons but different numbers of neutrons are called isotopes. Therefore, they have same atomic number while differ in mass number. Such as in C-12 and C-14.
Notes: Atoms that have the same number of protons but different numbers of neutrons are called isotopes. Therefore, they have same atomic number while differ in mass number. Such as in C-12 and C-14.
Q 37.Electrons move around the nucleus in which motion?
Answer: Correct Answer:C [orbital]
Notes: Electrons move around the nucleus in orbital motion. Such as motion involves the quantum mechanical motion of rigid particles (electrons in this case) about some other mass, or about themselves. Orbital motion involves translation of the center of mass rather than spin (rotation about the axis). Traditional physicists compare the movement of electrons as analogous to that of planetary motion around the sun.
Notes: Electrons move around the nucleus in orbital motion. Such as motion involves the quantum mechanical motion of rigid particles (electrons in this case) about some other mass, or about themselves. Orbital motion involves translation of the center of mass rather than spin (rotation about the axis). Traditional physicists compare the movement of electrons as analogous to that of planetary motion around the sun.
Q 38.What is the valency of magnesium?
Answer: Correct Answer:B [2]
Notes: Valency is number of electrons gain or loss to achieve noble gas configuration I.e. fully filled octet. Magnesium (Atomic number = 12) has electronic configuration 2, 8, 2. Since magnesium has 2 electrons in its outermost shell, hence it’s valency is 2, i.e., it will lose it’s 2 electrons to achieve noble gas configuration (2,8).
Notes: Valency is number of electrons gain or loss to achieve noble gas configuration I.e. fully filled octet. Magnesium (Atomic number = 12) has electronic configuration 2, 8, 2. Since magnesium has 2 electrons in its outermost shell, hence it’s valency is 2, i.e., it will lose it’s 2 electrons to achieve noble gas configuration (2,8).
Q 39.Isotopes of an element have ______:
Answer: Correct Answer:C [Different number of neutrons]
Notes: Atoms that have the same number of protons, but different numbers of neutrons are called isotopes. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively. The atomic number of carbon is 6, which means that every carbon atom has 6 protons, so that the neutron numbers of these isotopes are 6, 7 and 8 respectively.
Notes: Atoms that have the same number of protons, but different numbers of neutrons are called isotopes. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively. The atomic number of carbon is 6, which means that every carbon atom has 6 protons, so that the neutron numbers of these isotopes are 6, 7 and 8 respectively.
Q 40.Chlorine gas is a major component of which of the following?
Answer: Correct Answer:B [Tear gas]
Notes: Chlorine gas is a component of tear gas, also known as Chloroprene. The most commonly used tear gas contains the chemical agent 2- chlorobenzaldene malononitrile (CS). Despite its name, tear gas is not a gas, but an aerosol. CS is solid at room temperature and mixed with liquid or gas dispersal agents when used as a weapon designed to activate pain-sensing nerves.
Notes: Chlorine gas is a component of tear gas, also known as Chloroprene. The most commonly used tear gas contains the chemical agent 2- chlorobenzaldene malononitrile (CS). Despite its name, tear gas is not a gas, but an aerosol. CS is solid at room temperature and mixed with liquid or gas dispersal agents when used as a weapon designed to activate pain-sensing nerves.
Q 41.Which of the following elements are commonly found in most fertilizers?
Answer: Correct Answer:C [Nitrogen, Potassium, Phosphorus]
Notes: Nitrogen, phosphorus and potassium, or NPK, are the “Big 3” primary nutrients in commercial fertilizers. Each of these fundamental nutrients plays a key role in plant nutrition. Nitrogen is considered to be the most important nutrient, and plants absorb more nitrogen than any other element.
Notes: Nitrogen, phosphorus and potassium, or NPK, are the “Big 3” primary nutrients in commercial fertilizers. Each of these fundamental nutrients plays a key role in plant nutrition. Nitrogen is considered to be the most important nutrient, and plants absorb more nitrogen than any other element.
Q 42.Oxygen molecule is:
Answer: Correct Answer:B [Diatomic]
Notes: Oxygen is diatomic. Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements such as hydrogen (H2) or oxygen (O2). The prefix di- is of Greek origin, meaning “two”.
Notes: Oxygen is diatomic. Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements such as hydrogen (H2) or oxygen (O2). The prefix di- is of Greek origin, meaning “two”.
Q 43.The advantage of detergents over soaps is:
Answer: Correct Answer:C [Detergents give lather even with hard water]
Notes: 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 leading to loss of soap. Detergents react less to minerals in water and for all practical purposes are the product of choice for laundry.
Notes: 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 leading to loss of soap. Detergents react less to minerals in water and for all practical purposes are the product of choice for laundry.
Q 44.Washing soda is used:for removing permanent hardness of waterfor disinfecting drinking wateras a cleaning agent for domestic purposeWhich of the above is / are correct?
Answer: Correct Answer:B [Only 1 and 3]
Notes: Sodium carbonate (Na2CO3), also known as washing soda or soda ash, is used as a water softener in laundering. It competes with the magnesium and calcium ions in hard water and prevents them from bonding with the detergent being used. Sodium carbonate can be used to remove grease, oil, and wine stains. It is also used for removing the permanent hardness of water.
Notes: Sodium carbonate (Na2CO3), also known as washing soda or soda ash, is used as a water softener in laundering. It competes with the magnesium and calcium ions in hard water and prevents them from bonding with the detergent being used. Sodium carbonate can be used to remove grease, oil, and wine stains. It is also used for removing the permanent hardness of water.
Q 45.When a spoon is to be electroplated with nickel the spoon is:
Answer: Correct Answer:C [made cathode and a pure nickel red, the anode]
Notes: Electroplating is the deposition by electrolysis of a coating of metal upon a conducting surface. The simplest system makes the object to be plated the negative electrode (cathode) or plate in a galvanic couple. Thus, a spoon or other object may be connected by a wire to a plate of nickel. The process that occurs on the spoon is called reduction.
Notes: Electroplating is the deposition by electrolysis of a coating of metal upon a conducting surface. The simplest system makes the object to be plated the negative electrode (cathode) or plate in a galvanic couple. Thus, a spoon or other object may be connected by a wire to a plate of nickel. The process that occurs on the spoon is called reduction.
Q 46.The heat value of combustion of Gasoline is:
Answer: Correct Answer:D [47000 kJ/kg]
Notes: The calorific value of Gasoline is 47,000 kJ/kg. The calorific value of a fuel is the quantity of heat produced by its combustion – at constant pressure and under “normal” conditions (i.e. to 0oC and under a pressure of /atm).
Notes: The calorific value of Gasoline is 47,000 kJ/kg. The calorific value of a fuel is the quantity of heat produced by its combustion – at constant pressure and under “normal” conditions (i.e. to 0oC and under a pressure of /atm).
Q 47.Name the element that must be present in a compound to classify it as an organic compound.
Answer: Correct Answer:A [Carbon]
Notes: An organic compound must contain at least carbon. Most chemists agree hydrogen must also be present. Depending upon the arrangement of carbon atoms in their structure, organic compounds are broadly categorized into Acyclic or Open Chain compounds and Cyclic or Closed Chain compounds.
Notes: An organic compound must contain at least carbon. Most chemists agree hydrogen must also be present. Depending upon the arrangement of carbon atoms in their structure, organic compounds are broadly categorized into Acyclic or Open Chain compounds and Cyclic or Closed Chain compounds.
Q 48.Citric acid is present in free form in:
Answer: Correct Answer:D [Lemon]
Notes: Lemons, oranges, limes, and other citrus fruits naturally possess high concentrations of citric acid. The juice of the lemon is about 5% to 6% citric acid, which gives lemons a sour taste. Raw Amala is the richest source of citric acid among all citrus fruits.
Notes: Lemons, oranges, limes, and other citrus fruits naturally possess high concentrations of citric acid. The juice of the lemon is about 5% to 6% citric acid, which gives lemons a sour taste. Raw Amala is the richest source of citric acid among all citrus fruits.
Q 49.Which of the following has minimum ignition temperature?
Answer: Correct Answer:A [Petrol]
Notes: The minimum temperature at which a substance starts to burn is called its ignition temperature. Different fuels have different ignition temperatures. Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Examples include : petrol, diesel, alcohol, LPG, CNG etc.
Notes: The minimum temperature at which a substance starts to burn is called its ignition temperature. Different fuels have different ignition temperatures. Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Examples include : petrol, diesel, alcohol, LPG, CNG etc.
Q 50.What is the general formula of alkenes?
Answer: Correct Answer:A [CnH(2n)]
Notes: The generic formula for alanes is CnH2n+2, where n is the number identified by the prefix. Alkenes have the formula CnH2N. The general formula means that the number of hydrogen atoms in an alkene is double the number of carbon atoms. For example, ethene is C2H4 and propene is C3H6.
Notes: The generic formula for alanes is CnH2n+2, where n is the number identified by the prefix. Alkenes have the formula CnH2N. The general formula means that the number of hydrogen atoms in an alkene is double the number of carbon atoms. For example, ethene is C2H4 and propene is C3H6.