General Science Chemistry MCQs| Chemistry Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations

General Science Chemistry MCQs| Chemistry Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations.

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General Science – Chemistry MCQs

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General Science – Chemistry Quiz Multiple Choice Questions

General Science – Chemistry- General Knowledge Questions is one of the basic topics asked in each & every exams. Basic General Knowledge will help you in scoring good marks in all the competitive exams. Taking GK Quiz every month will be helpful. So, read the General Knowledge questions and answers and increase your Gk Quotient. The General Knowledge MCQs on current affairs will help you get good scores in UPSC, SSC or any other exams.

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General Science – Chemistry Multiple Choice Questions

1.The Alkali metals are called good reducing agents. This implies that__:

[A] They easily capture electrons
[B] They are not stable at room temperature
[C] They easily lose electrons
[D] They don’t act with dilute acids

Answer: C [They easily lose electrons ]

Notes:
Alkali metals have one electron in their valence shell and hence they easily lose or donate electron.

2.Which among the following is the objective of the Methyl tert-butyl ether (MTBE) mixing with Petroleum? 

[A] Raise Octane Number
[B] Antioxidant Stabilizer
[C] Lead Scavanger
[D] Fuel Dye

Answer: A [Raise Octane Number ]

Notes:

MTBE is a gasoline additive, used as an oxygenate to raise the octane number. Its use is controversial in the US and declining in that country in part because of its occurrence in groundwater and legislation favoring ethanol.

3.When a tube light breaks, a cracking sound is produced because ____?

[A] Pressure inside the lamp is less than atmospheric pressure
[B] Pressure inside the lamp is more than atmospheric pressure
[C] The lamp is filled with reactive gases
[D] The lamp is filled with mercury vapour

Answer: A [Pressure inside the lamp is less than atmospheric pressure ]

Notes:
A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. The pressure inside the lamp is around 0.3% of atmospheric pressure.

4.Consider the following statements:
1.’sweet’ crude is more valuable in comparison to ‘sour’ crude
2.Mumbai High crude produced by ONGC is sweet crude
Which among the above statements is / are correct?

[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2

Answer: C [ Both 1 & 2]

Notes:
Sulphur has to be removed during the refining process. Therefore, ‘sweet’ crude is more valuable compared to ‘sour’ crude. Mumbai High crude produced by ONGC is sweet crude.

5.Hypotonic solution is a solution:

[A] whose osmotic pressure is less than that of another
[B] which can dissolve maximum amount of solute at given temperature
[C] of solid in gas
[D] of solid in solid

Answer: A [ whose osmotic pressure is less than that of another]

Notes:
Hypotonic solution is a solution whose osmotic pressure is less than that of another.

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6.How the Cast Iron is different from Wrought Iron?

  1. Cast iron have higher carbon content than wrought iron 
  2. Cast iron are more ductile compared to wrought iron
  3. Wrought iron is more stable, pure and stronger, compared to cast iron

Select the correct option from the codes given below:

[A] 3 Only
[B] 1 and 3 Only
[C] 2 and 3 Only
[D] 1,2 and 3

Answer: B [ 1 and 3 Only]

Notes:
Second statement is wrong because wrought iron is more ductile compared to cast iron

7.Which of the following chemicals is also known as lachrymatory agent or lachrymator? 

[A] Mustard Gas
[B] Tear gas
[C] Diborane
[D] Chlorine gas

Answer: B [ Tear gas]

Notes:
Tear gas is also known as CS Gas. It acts as a lachrymatory agent. Tear gas irritate the mucous membrane of the eyes, nose, mouth and lungs, and causes tearing, coughing, burning and difficult breathing.

8.As per the Mohs scale of mineral hardness, which of the following are soft metals?

  1. Gold
  2. Copper
  3. Diamond
  4. Thorium

Select the correct option from codes given below:

[A] 1 & 4 Only
[B] 1, 2 & 4 Only
[C] 2 & 4 Only
[D] 1, 2, 3 & 4

Answer: B [ 1, 2 & 4 Only]

Notes:
As per the Mohs scale of mineral hardness, the soft metals are: Lead, gold, silver, tin, zinc, aluminium, thorium, copper, brass and bronze. Diamond is one of the hardest known metals on earth.

9.The patient is instructed to drink which of the following solutions before undergoing radiological examinations?

[A] Barium sulphate
[B] Sodium chloride
[C] Strontium phosphate
[D] Germanium tetrachloride

Answer: A [ Barium sulphate]

Notes:
The patient is made to drink Barium sulphate suspension before he/she undergoes examination of the upper gastrointestinal (GI) tract, specifically the pharynx, the esophagus, stomach, and duodenum. Barium is a highly reactive element and hence is not found in nature as a free element.

10.For most liquids, viscosity increases with increasing:

  1. Pressure
  2. Temperature
  3. Surface tension

Select the correct option from codes given below:

[A] 1 & 3 Only
[B] 2 & 3 Only
[C] 3 Only
[D] 1, 2 & 3

Answer: A [ 1 & 3 Only]

Notes:
In liquids main cause of viscosity is cohesion between the molecules. As the temperature of a liquid increases, its surface tension decreases.The viscosity of liquids reduce with increase in temperature.

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11.What is the atomic number of Barium?

[A] 54
[B] 56
[C] 58
[D] 60

Answer: B [56]

Notes:
The atomic number of barium is 56.

12.Which of the following is the use of washing soda?

[A] softening of water
[B] manufacture of glass
[C] manufacture of paints
[D] All of the above

Answer: D [All of the above]

Notes:
It is used for softening of water, laundering, cleaning, manufacture of glass, soap, borax, paper, paints and textile It is also extensively used as laboratory reagent.

13.What is the chemical name of Quick lime?

[A] Calcium peroxide
[B] Calcium oxide
[C] Calcium dioxide
[D] Calcium hydroxide

Answer: B [Calcium oxide]

Notes:
The chemical name of Quick Lime is Calcium Oxide (CaO).

14.Which of the following is NOT correct about the use of Quick lime?

[A] Manufacturing of cement
[B] Manufacture of sodium carbonate
[C] Purification of sugar
[D] used to extinguish fire

Answer: D [used to extinguish fire]

Notes:
(i) It is an important primary material for manufacturing cement and is the cheapest form of alkali. (ii) It is used in the manufacture of sodium carbonate from caustic soda. (iii) It is employed in the purification of sugar and in the manufacture of dye stuffs.

15.What is the general trend for atomic radii of alkali metals as we move down the group?

[A] it increases
[B] it decreases
[C] it remains constant
[D] None of the above

Answer: A [it increases]

Notes:
The atomic and ionic radii of alkali metals increase on moving down the group i.e., they increase in size while going from Li to Cs.

16.Which of the following are the uses of Calcium carbonate?

[A] as an antacid
[B] mild abrasive in tooth paste
[C] as a filler in cosmetics
[D] All of the above

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.

17.Which of the following is correct about Potassium carbonate?

[A] Its chemical formula is K CO3
[B] It is a salt which is white in colour
[C] It is used in the production of soap
[D] All of the above

Answer: D [All of the above]

Notes:
Potassium carbonate is a salt which is white in colour. It is used in the production of soap. Its chemical formula is K2 CO3.

18.Which of the following metal is the main constituent in Pewter alloy?

[A] Lead
[B] Zinc
[C] Tin
[D] Iron

Answer: C [Tin]

Notes:
The term pewter covers a variety of alloys consisting primarily of tin. It is composed of 85–99% tin, mixed with copper, antimony, bismuth, silver or lead..

19.Which of the following is correct about Solder?

[A] It is an alloy of lead and tin
[B] It is used for welding electrical wires together
[C] It has a low melting point
[D] All of the above

Answer: D [All of the above]

Notes:
Solder is an alloy of lead and tin (Pb and Sn). It has a low melting point and is used for welding electrical wires together.

20.Choose the incorrect ‘Alloy – constituent metal’ pair:

[A] Lockalloy – Iron
[B] Vitallium – Cobalt
[C] Italma – Aluminium
[D] Constantan – Copper

Answer: A [Lockalloy – Iron]

Notes:
Lockalloy is an alloy that contains 62% beryllium and 38% aluminum. All other pairs are correctly matched.

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21.What will be the number of neutrons in an atom having atomic number 35 and mass number 80?

[A] 35
[B] 45
[C] 55
[D] 80

Answer: B [45]

Notes:
The total number of nucleons is termed as mass number (A) of the atom. In this case, mass number is 80. Therefore, sum of the number of neutrons and protons is 80. As atomic number is 35, we know that number of protons is 35. Hence, number of neutrons = 80-35 = 45.

22.Which of the following is correct about Photoelectric effect?

[A] number of electrons ejected is twice the wavenumber of radiation
[B] number of electrons ejected is proportional to the intensity of light
[C] number of electrons ejected is proportional to the duration of light
[D] number of electrons ejected is not dependent on the intensity of light

Answer: B [number of electrons ejected is proportional to the intensity of light]

Notes:
The phenomenon of ejection of electrons from the surface of metal when light of suitable frequency strikes it is called photoelectric effect. The number of electrons ejected is proportional to the intensity or brightness of light.

23.What do we call the difference between the initial mass energy and the total mass energy of the decay products in a radioactive decay?

[A] entropy
[B] disintegration energy
[C] alpha energy
[D] integration energy

Answer: B [disintegration energy]

Notes:
The disintegration energy or the Q-value of a nuclear reaction is the difference between the initial mass energy and the total mass energy of the decay products.

24.Which of the following represents the reaction of Calcium oxide and water to form Slaked lime?

[A] Displacement reaction
[B] Combination reaction
[C] Double Displacement reaction
[D] None

Answer: B [Combination reaction]

Notes:
A reaction in which a single product is formed from two or more reactants is known as a combination reaction. For example: calcium oxide and water combine to form a single product, slaked lime or calcium hydroxide.

25.Which of the following equation represents combination of Hydrogen gas with nitrogen to form ammonia?

[A] 2H2 + N –> NH3
[B] 2H + N3 –> NH3
[C] 3H2 + N2 –> 2NH3
[D] None of the above

Answer: C [3H2 + N2 –> 2NH3]

Notes:
3H2 + N2 –> 2NH3 is the balance equation which represents combination of Hydrogen gas with nitrogen to form ammonia.

26.Which of the following is the unit of rate of chemical reaction?

[A] Mol L s-1
[B] Mol L2 s-1
[C] Mol L-1 s-1
[D] Mol L-1 s-2

Answer: C [Mol L-1 s-1]

Notes:
If concentration is in mol L-1 and time is in seconds then the units will be Mol L-1 s-1. However, in gaseous reactions, when the concentration of gases is expressed in terms of their partial pressures, then the units of the rate equation will be atm s–1.

27.What is the general trend for electronegativity in a group of the periodic table as we move from top to bottom?

[A] It increases
[B] It decreases
[C] It remains constant
[D] None

Answer: B [It decreases]

Notes:
Electronegativity generally increases across a period from left to right (say from lithium to fluorine) and decrease down a group (say from fluorine to astatine) in the periodic table.

28.Choose the correct statement about the modern periodic table:

[A] Elements in any one group contain the same number of valence electrons
[B] Elements in any one period contain the same number of shells
[C] Both a and b
[D] None

Answer: C [Both a and b]

Notes:
Elements present in any one group of the modern periodic table have the same number of valence electrons. Elements in any one period contain the same number of shells.

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29.Which of the following molecules have a T-shape arrangement?

[A] Ozone
[B] Water
[C] Chlorine Trifluoride
[D] Sulphur dioxide

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.

30.Choose the correct statement about covalent compounds?

[A] The forces of interaction between them is weak
[B] They are poor conductors of electricity
[C] Both a and b
[D] None of the above

Answer: C [Both a and b]

Notes:
The covalent compounds have low melting and boiling points due to weak forces of interaction between the molecules. The covalent compounds are poor conductors of electricity as these lack ionic species.

31.What do we call the cell potential when no current is drawn through the galvanic cell?

[A] Zero potential
[B] E.M.F
[C] Equilibrium potential
[D] None of the above

Answer: B [E.M.F]

Notes:
The cell potential is called the cell electromotive force (emf) of the cell when no current is drawn through the cell. Also, It is now an accepted convention that we keep the anode on the left and the cathode on the right while representing the galvanic cell.

32.What is the effect of increase in concentration on the Molar conductivity?

[A] It increases
[B] It decreases
[C] It remains constant
[D] None of the above

Answer: B [It decreases]

Notes:
Molar conductivity increases with decrease in concentration and decreases with increase in concentration. This is because the total volume of solution containing one mole of electrolyte also increases as the concentration decreases.

33.Which of the following is correct about a strong electrolyte?

[A] It is a good conductor of electricity
[B] Molar conductivity increases slowly with dilution
[C] Both a and b
[D] None

Answer: C [Both a and b]

Notes:
The ions of strong electrolytes are good conductors of electricity in the solution. The Molar conductivity in case of strong electrolytes increases slowly with dilution.

34.Which of the following is not a compound of carbon?

[A] Cinnabar
[B] Acetic acid
[C] Chloroform
[D] Methane

Answer: A [Cinnabar]

Notes:
Acetic acid, Chloroform and Methane are some of the compounds of carbon. Cinnabar which is also known as Mercury Sulphide is a compound of Mercury and Sulphur.

35.Which of the following is / are correct statements with respect to Graphite?

  1. It is the most stable phase of carbon at normal conditions
  2. It is made of made of sp3 hybridized carbon atoms
  3. It is good conductor of both heat and electricity

Select the correct option from the codes given below:

[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3

Answer: C [Only 1 & 3 ]

Notes:
Graphite is an allotrope of Carbon. It is a good conductor of electricity as well as heat. It is also most stable phase of carbon at normal conditions. It is made of made out of sp2 hybridized carbon atoms.

36.Which of the following represents Isocyanic acid?

[A] HNCO
[B] CNO
[C] HCO
[D] HNC

Answer: A [HNCO]

Notes:
Isocyanic acid is a chemical compound with the formula HNCO. It was discovered in 1830 by Liebig and Wohler. It is a colourless substance which is volatile and poisonous. It is the simplest stable chemical compound containing carbon, hydrogen, nitrogen, and oxygen.

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37.Which of the following is an organic compound?

[A] Carbon disulfide – CS2
[B] Carbon monoxide – CO
[C] Carbon tetrabromide – CBr4
[D] Carbon tetrachloride – CCl4

Answer: D [Carbon tetrachloride – CCl4]

Notes:
Carbon tetrachloride – CCl4 is traditionally considered to be an organic compound despite not having H atoms.

38.Which of the following chemical is produced when Ethene reacts with cold aqueous solution of Bayer’s reagent?

[A] Methanol
[B] Glycol
[C] Methanal
[D] Ethyne

Answer: B [Glycol]

Notes:
Alkenes on reaction with cold, dilute, aqueous solution of potassium permanganate (Baeyer’s reagent) produce vicinal glycols.

39.Which of the following metals is a bad conductor of heat?

[A] Copper
[B] iron
[C] Lead
[D] Cobalt

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.

40.Which of these elements is used as a dopant in n-type silicon wafers?

[A] Antimony
[B] Iodine
[C] Carbon
[D] Radon

Answer: A [ Antimony ]

Notes:
Antimony is used in semiconductors as a dopant in n-type silicon wafers for diodes, infrared detectors, and Hall-effect device. Antimony is a gray metalloid having atomic number 51.

41.Which metal has the highest melting point among all metals?

[A] Tungsten
[B] Ruthenium
[C] Gold
[D] Bismuth

Answer: A [Tungsten]

Notes:
Of all the metals, Tungsten has the highest melting point (3422 °C). Also, it has the lowest vapor pressure and the highest tensile strength among all the metals.

42.Which of the following salts of long chain carboxylic acids are the detergents commonly made up of?

[A] ammonium and sulphonate
[B] calcium and magnesium
[C] cobalt and nitrate
[D] None of the above

Answer: A [ammonium and sulphonate]

Notes:
Detergents are generally ammonium or sulphonate salts of long chain carboxylic acids. Detergents are usually used to make shampoos and products for cleaning clothes.

43.Which of the following detergents represent the liquid dishwashing detergents?

[A] Anionic
[B] Cationic
[C] Non-ionic
[D] None of the above

Answer: C [Non-ionic]

Notes:
Liquid dishwashing detergents are of non-ionic type. Non-ionic detergents do not contain any ion in their constitution.

44.What is the chemical formula of Stearic acid?

[A] C17H34CO2H
[B] C17H35CO2H
[C] C18H36CO2H
[D] None of the above

Answer: B [C17H35CO2H]

Notes:
Stearic acid is a waxy solid and its chemical formula is C17H35CO2H. It is a raw material for the saponification process.

45.Cream gets separated out of milk when it is churned due to which of the following reasons?

[A] Gravitational pull
[B] Centripetal force
[C] Centrifugal force
[D] Frictional force

Answer: C [Centrifugal force]

Notes:
When Milk is churned vigorously the cream from it is separated out due to Centrifugal Force. Churning physically agitates the cream until it ruptures the fragile membranes surrounding the milk fat.

46.Which metal is usually extracted from sea water?

[A] Ca
[B] Na
[C] K
[D] Mg

Answer: D [Mg]

Notes:
In the US, 63% of magnesium production came from seawater. The Metal is extracted from seawater and brines by means of electrolysis, a process that requires the passing of a current through a molten salt. This extracts the metal from the salt, but requires a high temperature to melt the salt.

47.Chewing gum is made from which of the following?

[A] Resin
[B] Polystyrene
[C] Polyvinyl acetate
[D] Latex

Answer: D [Latex]

Notes:
Chewing gum was made of a substance called chicle mixed with flavorings. Chicle is a latex sap that comes from the sapodilla tree (native to Central America).

48.After soil test of an area, it is found that the soil in the field is highly acidic. Which of the following two materials would you suggest to be added to this soil to reduce its acidity?

[A] Lime and Gypsum
[B] Gypsum and Chalk
[C] Lime and Chalk
[D] Lime and Urea

Answer: C [Lime and Chalk]

Notes:
Lime (CaO) and Chalk (CaCO3) can also be added to neutralize acidity of the soil. It is because CaO and CaCO3 are basic in nature which can neutralize the acid present in the soil. Gypsum and Urea are used to treat alkaline soil rather.

49. Biogas is composed of Oxygen, Carbon dioxide, Nitrogen, Hydrogen, Methane and Hydrogen Sulphide compounds. Which one of the following compounds forms the majority?

[A] Carbon dioxide
[B] Carbon monoxide
[C] Hydrogen sulphide
[D] Methane

Answer: D [Methane ]

Notes:

Biogas or Gobar gas is produced by the anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops. It comprises primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes.

The composition of biogas varies depending upon the substrate composition, as well as the conditions within the anaerobic reactor (temperature, pH, and substrate concentration). Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55%–75% methane, which for reactors with free liquids can be increased to 80%–90% methane using in-situ gas purification techniques.

As produced, biogas contains water vapour. The fractional volume of water vapour is a function of biogas temperature; correction of measured gas volume for water vapour content and thermal expansion is easily done via simple mathematics which yields the standardized volume of dry biogas.

50.Which one of the following forms the chief constituent of Vinegar?

[A] Formic acid
[B] Acetic acid
[C] Salicylic acid
[D] Oxalic acid

Answer: B [Acetic acid ]

Notes:

Vinegar is a liquid substance consisting mainly of acetic acid (CH3CO2H) and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. It is today mainly used in the kitchen as a general cooking ingredient, but historically, as the most easily available mild acid, it had a great variety of industrial, medical, and domestic uses. Vinegar is a liquid that is produced from the fermentation of ethanol into acetic acid.

The fermentation is carried out by bacteria. Vinegar consists of acetic acid (CH3COOH), water and trace amounts of other chemicals, which may include flavourings. The concentration of the acetic acid is variable. Distilled vinegar contains 5-8% acetic acid. Spirit of vinegar is a stronger form of vinegar that contains 5-20% acetic acid. Flavourings may include sweeteners, such as sugar or fruit juices. Infusions of herbs, spices and other flavours may be added, too.

Vinegar is made from a variety of source materials. Each contributes its own unique flavour signature to the final product. Vinegar may be made from sugar cane juice, rice and other grains, grapes (balsamic vinegar), coconut water, fruit wines, kombucha, or apple cider. Spirit vinegar is a strong variety of vinegar (5% to 21% acetic acid) made from sugar cane and doubly fermented. The first fermentation changes sugar into alcohol, while the second fermentation changes alcohol into acetic acid.

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