Updated December 20, 2022
Chemistry GS Objective Questions featured on this page is result of sincere efforts put in by the team Career101.in. These questions are from length and breadth of Chemistry GS and they test your actual acumen which is very much required in making through the Government Jobs. In terms of assessment standards the objective questions asked from Chemistry GS can at times intriguing and you may not find at ease solving them. So, in its endevour to support your preparation for competitive exams, the compilation made by the team has put in hours quality time in matching the standard. The team hopes the collection below comes in really handy when you need it most.
1. Which of the following compound of sodium is generally prepared by Solvay process?
[A] Sodium Carbonate
[B] Sodium Hydroxide
[C] Sodium Chloride
[D] All of the above
Correct Answer: [Sodium Carbonate]
Explanation: Sodium carbonate is generally prepared by Solvay Process.
2. Which of the following statements about alkali metals is correct?
[A] lithium is the most powerful reducing agent
[B] Sodium is the least powerful reducing agent
[C] Both a and b
[D] None
Correct Answer: [Both a and b]
Explanation: Lithium is least reactive but the strongest reducing agent among all the alkali metals.
3. What is the order of distance for Vander Wall forces to be active?
[A] 10–6 metre
[B] 10–7 metre
[C] 10–8 metre
[D] 10–9 metre
Correct Answer: [10–9 metre]
Explanation: The forces between the molecules because of the electrostatic interaction between the charges of the molecules are called intermolecular forces. These forces are also called Vander Waal forces. They are quite weak as compared to inter-atomic forces. These forces are also electrical in nature. They are active if the separation between two molecules is of the order of molecular size i.e. 10–9 metre.
4. What is the equilibrium distance for Hydrogen atoms?
[A] 0.54 Å
[B] 0.64 Å
[C] 0.74 Å
[D] 0.84 Å
Correct Answer: [0.74 Å]
Explanation: When the interatomic force between two atoms is zero, the distance between them is called as normal or equilibrium distance. The equilibrium distance for Hydrogen atoms is 0.74 Å.
5. What is the order of distance for interatomic forces to be active?
[A] 10–7 metre
[B] 10–8 metre
[C] 10–9 metre
[D] 10–10 metre
Correct Answer: [10–10 metre]
Explanation: The forces between the atoms because of the electrostatic interaction between the charges of the atoms are called interatomic forces. These forces are active if the distance between the two atoms is of the order of atomic size i.e. 10–10 metre. These forces are electrical in nature.
6. What is Young’s Modulus?
[A] ratio of longitudinal strain to normal stress
[B] product of normal stress of longitudinal strain
[C] ratio of normal stress to longitudinal strain
[D] ratio of normal stress to lateral strain
Correct Answer: [ratio of normal stress to longitudinal strain]
Explanation: Young’s Modulus is defined as the ratio of normal stress to longitudinal strain within limit of proportionality. Y = normal stress/longitudinal strain.
7. Which of the following relations between Kinetic energy and Potential energy is true about solids?
[A] Kinetic energy = Potential energy
[B] Kinetic energy > Potential energy
[C] Kinetic energy >> Potential energy
[D] Kinetic energy < Potential energy
Correct Answer: [Kinetic energy < Potential energy]
Explanation: In Solids, Kinetic energy is always less than the Potential energy. For liquids, Kinetic energy > Potential energy. For Gases, Kinetic energy >> Potential energy.
8. Which of the following is incorrect about the Inter atomic and Intermolecular Forces?
[A] Both the forces are electrical in origin
[B] Both the forces are active over short distances
[C] General shape of force-distance graph is similar for both the forces
[D] None of the above
Correct Answer: [None of the above]
Explanation: Comparison between Inter atomic and Intermolecular Forces: (i) Both Inter atomic and Intermolecular forces are electrical in origin. (ii) Both Inter atomic and Intermolecular forces are active over short distances. (iii) General shape of force-distance graph for both the forces is similar. (iv) Both the forces are attractive up to certain distance between atoms/molecules and become repulsive when the distance between them becomes less than that value.
9. Which among the following was first human-made plastic?
[A] Bakelite
[B] Polyethene
[C] Celluloid
[D] Nylon
Correct Answer: [Celluloid]
Explanation: The first human-made plastic was made by Alexander Parkes in 1855, when he synthesized celluloid. The new discovery found its use in photographic films, but it could not be used for making containers or insulators for electric circuits.
The first true plastic was made in 1909 by Leo Baekeland, who synthesized Bakelite. The hard plastic could be used to make handles, auto parts, etc. The First World War witnessed improvements in the manufacture of polystyrene and polyvinyl chloride, which found use in plumbing equipment and electric wire insulation. Nylon was synthesized in the 1930s. By 1950, plastics became quite popular and as a result we can see them everywhere today.
10. Who among the following established that genetic code of all organisms is spelled out in three-letter words, each set of three nucleotides codes for a specific amino acid?
[A] Hargobind Khorana
[B] Barbara McClintock
[C] Theodor O. Diener
[D] Joseph L. Goldstein
Correct Answer: [Hargobind Khorana]
11. PVC is a polymer of?
[A] Propane
[B] Vinyl chloride
[C] Styrene
[D] Carbonates
Correct Answer: [Vinyl chloride]
Explanation: Polyvinyl chloride (PVC) is made from the monomer vinyl chloride (CH2 =CHCl). It is used for making rain coats, handbags, toys including dolls, electrical goods and as a covering of electrical wires.
12. The easily noticed smell of the LPG gas is because of which among the following?
[A] Butane
[B] Propane
[C] Methane
[D] Ethanethiol
Correct Answer: [Ethanethiol]
Explanation: Ethanethiol or stench, is an organosulfur compound and is used to add to the otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks.
13. Calamine is an ore of which among the following?
[A] Zinc
[B] Copper
[C] Mercury
[D] Iron
Correct Answer: [Zinc]
Explanation: Calamine- ZNCO3
14. Which among the following is known as White Vitriol?
[A] Zinc Sulphate
[B] Zinc Chloride
[C] Zinc Phosphate
[D] Zinc oxide
Correct Answer: [Zinc Sulphate]
15. “Atoms can neither be created nor destroyed.” This principle was given by __?
[A] Avogadro
[B] Dalton
[C] Rutherford
[D] Niels Bohr
Correct Answer: [Dalton]
Explanation: The given principle is one of the postulates of the Dalton’s atomic theory given in 1803 by John Dalton. The postulates of Dalton’s atomic theory are as follows:
I. Elements consist of indivisible small particles (atoms).
II. All atoms of the same element are identical; different elements have different types of atom.
III. Atoms can neither be created nor destroyed.
IV. ‘Compound elements’ (i.e. Compounds) are formed when atoms of different elements join in simple ratios to form ‘compound atoms’ (i.e. Molecules).
16. Which among the following gas was leaked at Bhopal during the Bhopal gas tragedy at 2-3 December 1984?
[A] Methyl isocyanide
[B] Methyl isocyanate
[C] Methyl isochloride
[D] Methyl isochlorate
Correct Answer: [Methyl isocyanate]
In the night of 2-3 December, 1984, the Union Carbide subsidiary pesticide plant in Bhopal released around 40 tonnes of toxic methyl isocyanate (MIC) gas. More than 500000 people got exposed to the gas and more than 4000 died.
17. 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
Correct Answer: [Raise Octane Number]
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.
18. Presence of which among the following minerals in Banana makes them slightly radioactive?
[A] Sodium
[B] Calcium
[C] Magnesium
[D] Pottasium
Correct Answer: [Pottasium]
Explanation: Slight radioactivity of Banana is due to presence of K-40.
19. Which of the following is the essential element for batteries used in electric cars?
[A] Magnesium
[B] Lithium
[C] Sodium
[D] Bromine
Correct Answer: [Lithium]
Explanation: The lithium-ion batteries needed to power electric cars use lithium carbonate or lithium hydroxide.
20. Gold Ring which is 50% pure. Its purity can be alternatively shown as __:
[A] 18 Carat
[B] 18 Karat
[C] 12 Carat
[D] 12 Karat
Correct Answer: [12 Karat]
Explanation: The carat is the common unit used to describe the mass of a gem. A 1-carat diamond, for example, has a mass of 0.20 g. The karat is the common unit used to describe the purity of a precious metal, such as gold. A 24-karat gold ring is as pure as can be. A gold ring that is 50 % pure is 12 karat.
21. What will happen if a wire of length L is cut into two or more parts?
[A] each part can hold half the weight as full-length wire
[B] each part can hold the same weight as full-length wire
[C] each part can hold twice the weight as full-length wire
[D] None of the above
Correct Answer: [each part can hold the same weight as full-length wire]
Explanation: If a wire of length L is cut into two or more parts, then it’s each part can hold the same weight. Since breaking force is independent of the length of wire.
22. Which of the following element has the highest first ionization enthalpy?
[A] Magnesium
[B] Strontium
[C] Beryllium
[D] Barium
Correct Answer: [Beryllium]
Explanation: The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases.
23. Which of the following compound of sodium is generally prepared by Solvay process?
[A] Sodium Carbonate
[B] Sodium Hydroxide
[C] Sodium Chloride
[D] All of the above
Correct Answer: [Sodium Carbonate]
Explanation: Sodium carbonate is generally prepared by Solvay Process.
24. What is the electron configuration of Radium?
[A] 6s2
[B] 7s2
[C] 7s2 7p6
[D] 7s2 7p4
Correct Answer: [7s2]
25. How many groups of p–block elements are there in the periodic table?
[A] 4
[B] 6
[C] 8
[D] 3
Correct Answer: [6]
Explanation: There are six groups of p–block elements in the periodic table numbering from 13 to 18.
26. What happens to the non-metallic character of elements in the p-block of the periodic table?
[A] non-metallic character decreases down the group
[B] non-metallic character increases down the group
[C] No fix pattern
[D] None
Correct Answer: [non-metallic character decreases down the group]
Explanation: The non-metallic character of elements decreases down the group. In fact, the heaviest element in each p-block group is the most metallic in nature.
27. What is the general outer electron configuration of Group 13 elements?
[A] ns2 np2
[B] ns2
[C] ns2 np1
[D] ns2 np3
Correct Answer: [ns2 np1]
28. Which of the following is NOT correct about Xenon Hexafluoride?
[A] It is a noble gas compound
[B] At room temperature, it is a colourless liquid
[C] Both a and b
[D] None
Correct Answer: [At room temperature, it is a colourless liquid]
Explanation: Xenon Hexafluoride is a noble gas compound which is a colourless solid at room temperature. Its chemical formula is XeF6
29. Which of the following is correct about Potassium sodium tartrate tetrahydrate?
[A] It is also known as Globular,s salt
[B] It is known to exhibit piezoelectricity
[C] Both a and b
[D] None of the above
Correct Answer: [It is known to exhibit piezoelectricity]
Explanation: Potassium sodium tartrate tetrahydrate is commonly called as Rochelle salt. It was one of the first materials discovered to exhibit piezoelectricity.
30. Which of these is NOT a compound of carbon?
[A] Acetic acid
[B] Chloroform
[C] Caustic Soda
[D] Methane
Correct Answer: [Caustic Soda]
Explanation: Caustic soda is a compound of sodium whereas Acetic acid, Chloroform and Methane are the compounds of carbon.
31. Which of the following Metal-Ore pairs is not correct?
[A] Iron & Magnetite
[B] Alluminium & Bauxite
[C] Gold & Calaverite
[D] Calcium & Carnalite
Correct Answer: [Calcium & Carnalite]
Explanation: Carnalite is an ore of Potassium. It’s a hydrated potassium magnesium chloride. The chemical formula of Carnalite is KCl. MgCl.
32. Which of the following metal has an ore named as Cassiterite?
[A] Bismuth
[B] Antimony
[C] Tin
[D] Uranium
Correct Answer: [Tin]
Explanation: Cassiterite is a tin oxide mineral. Its chemical formula is SnO2. It is the only commercially important source of tin. Cassiterite is generally opaque.
33. Which of the following is the purest form of Iron?
[A] Pig iron
[B] Cast iron
[C] Wrought iron
[D] None of the above
Correct Answer: [Wrought iron]
Explanation: Wrought iron is the purest form of iron. Pig iron has about 4% of carbon and some other impurities. Cast iron has about 3% of carbon content.
34. Which of the following refining methods works on the principle of adsorbtion?
[A] Zone refining
[B] Vapour Phase refining
[C] Chromatographic methods
[D] Liquation
Correct Answer: [Chromatographic methods]
Explanation: Chromatographic methods are based on the principle that different components of a mixture are differently adsorbed on an adsorbent. There are several chromatographic techniques used for refining such as paper chromatography, column chromatography, gas chromatography, etc.
35. Which of the following was discovered in Milikan’s oil drop experiment?
[A] Charge on a proton
[B] Charge on an electron
[C] Charge to mass ratio of an electron
[D] Mass of a Hydrogen atom
Correct Answer: [Charge on an electron]
Explanation: R.A. Millikan devised a method known as oil drop experiment (1906-14), to determine the charge on the electrons. As per the experiment, the charge on the electron was found to be – 1.6 × 10–19C.
36. Which of the following does not represent the Atomic number of an atom?
[A] number of protons in the nucleus of an atom
[B] number of electrons in a neutral atom
[C] number of neutrons in the nucleus of an atom
[D] None of the above
Correct Answer: [number of neutrons in the nucleus of an atom]
Explanation: The number of protons present in the nucleus of an atom or the number of electrons in a neutral atom is equal to its atomic number. It is represented by Z.
37. What is the relationship between becquerel and curie unit?
[A] 1 curie = 0.5 Bq
[B] 1 curie = 9 × 106 Bq
[C] 1 curie = 3.7 × 1010 Bq
[D] 1 curie = 5.7 Bq
Correct Answer: [1 curie = 3.7 × 1010 Bq]
Explanation: 1 curie = 1 Ci = 3.7 × 1010 decays per second = 3.7 × 1010Bq. This is approximately the amount of radioactivity emitted by one gram (1 g) of radium-226. The “curie” unit is named after Pierre Curie, a French physicist.
38. Which of the following is emitted in Beta-decay process?
[A] Electron
[B] Positron
[C] Both a and b
[D] None
Correct Answer: [Both a and b]
Explanation: In beta decay, a nucleus spontaneously emits an electron (βdecay) or a positron (β+decay). One can never predicts which nucleus will undergo decay.
39. Who is known as the Father of Radioactivity?
[A] Marie Skłodowska-Curie
[B] Pierre Curie
[C] Antoine Henri Becquerel
[D] Wilhelm Conrad Rontgen
Correct Answer: [Antoine Henri Becquerel]
Explanation: Antoine Henri Becquerel was the first person to discover evidence of radioactivity. He was a French physicist and was awarded Nobel prize in Physics in the year 1903.
40. Which of the following is emitted in alpha decay?
[A] Helium nucleus
[B] Hydrogen nucleus
[C] Electrons
[D] Carbon nucleus
Correct Answer: [Helium nucleus]
Explanation: In alpha decay, Helium nucleus is emitted. Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus transforms or decays into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.
41. What is the S.I unit of frequency?
[A] Second
[B] Watt
[C] Hertz
[D] Joule
Correct Answer: [Hertz]
Explanation: The frequency is defined as the number of periodic motions executed by body per second. The S.I unit of frequency is hertz (Hz).
42. When are the two particles said to be in same phase?
[A] if the phase difference between them is an even multiple of π
[B] if the path difference is an even multiple of (λ / 2)
[C] if the time interval is an even multiple of (T/ 2)
[D] All of the above
Correct Answer: [All of the above]
Explanation: Two vibrating particle are said to be in same phase, if the phase difference between them is an even multiple of π or path difference is an even multiple of (λ / 2) or time interval is an even multiple of (T/ 2).
43. What is the effect of rise of temperature on the time period of a simple pendulum?
[A] it increases
[B] it decreases
[C] it may or may not increase
[D] No relationship
Correct Answer: [it increases]
Explanation: If the bob of simple pendulum is suspended by a wire then effective length of pendulum will increase with the rise of temperature due to which the time period will increase.
44. What will be the spring constant of each part if the spring of force constant k is divided into n equal parts?
[A] k
[B] k/n
[C] nk
[D] kn
Correct Answer: [nk]
Explanation: If the spring of force constant k is divided into n equal parts then spring constant of each part will become nk.
45. Which of these is NOT an example of Periodic motion?
[A] Revolution of earth around the sun
[B] Rotation of earth about its polar axis
[C] Motion of minute’s hand of a clock
[D] None of the above
Correct Answer: [None of the above]
Explanation: Examples of Periodic motion: (i) Revolution of earth around the sun (period one year) (ii) Rotation of earth about its polar axis (period one day) (iii) Motion of hour’s hand of a clock (period 12-hour) (iv) Motion of minute’s hand of a clock (period 1-hour) (v) Motion of second’s hand of a clock (period 1-minute) (vi) Motion of moon around the earth (period 27.3 days)
46. Which of the following is correct about transverse mechanical waves?
[A] they can travel through solids and gases
[B] they can travel through solids but not liquids
[C] they can travel through solids and liquids
[D] they can travel through gases but not solids
Correct Answer: [they can travel through solids but not liquids]
Explanation: In transverse waves, the constituents of the medium oscillate perpendicular to wave motion subjecting each element of the medium to shearing stress. Solids and strings have shear modulus, that is they sustain shearing stress. Fluids have no shape of their own, they yield to shearing stress. This is why transverse waves are possible in solids and strings (under tension) but not in fluids.
47. What is the S.I unit of the propagation constant?
[A] radian metre
[B] radian per metre
[C] radian per second
[D] radian per centimetre
Correct Answer: [radian per metre]
Explanation: The SI unit of propagation constant is radian per metre. It is also known as the angular wave number and represented by K.
48. Which of the following are the areas of application of Doppler’s effect?
[A] At airports to guide aircraft
[B] in the military to detect enemy aircraft
[C] Sonography
[D] All of the above
Correct Answer: [All of the above]
Explanation: The change in frequency caused by a moving object due to Doppler effect is used to measure their velocities in diverse areas. It is used by police to check over-speeding of vehicles. It is used at the airports to guide aircraft, and in the military to detect enemy aircraft. Doctors use it to study heart beats and blood flow in different parts of the body. Here they use ultrasonic waves, and in common practice, it is called as sonography.
49. What is the wavelength of a stationary wave?
[A] twice the distance between two consecutive nodes or antinodes
[B] equal to the distance between two consecutive nodes or antinodes
[C] half the distance between two consecutive nodes or antinodes
[D] four times the distance between two consecutive nodes or antinodes
Correct Answer: [twice the distance between two consecutive nodes or antinodes]
Explanation: Wavelength (λ) of a progressive wave is the distance between two consecutive points of the same phase at a given time. In a stationary wave, it is twice the distance between two consecutive nodes or antinodes.
50. Which of the following is correct about the electromagnetic waves?
[A] They require a solid medium to travel
[B] They can travel through vacuum
[C] Electromagnetic waves can only travel through gases
[D] None of the above
Correct Answer: [They can travel through vacuum]
Explanation: Electromagnetic waves do not necessarily require a medium, they can travel through vacuum, Light, radio waves, X-rays, are all electromagnetic waves.