General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
1. Which of the following is / are correct statements with respect to Copper (Cu), Silver (Ag) and Gold (Au)?
1. All of them are can be found naturally in their elemental state
2. All of them belong to same group in the periodic table
Select the correct option from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [ Both 1 & 2 ]
Notes:
The elements Copper (atomic number 29), silver (atomic number 47), and gold (atomic number 79), are three of the few metals that can be found naturally in their elemental state. These three metals have found great use as coins and jewellery for a number of reasons, including their resistance to corrosion and their remarkable colors. They are all in the same group in the periodic table (group 11), which suggests they should have similar—though not identical—properties.
2. Which among the following is the correct set of chemical formulae of Chile Saltpetre, Saltpetre and Quick Lime?
[A] KNO3, NaNO3, CaO
[B] NaNO3, KNO3, Ca(OH)2
[C] Na(OH)2, KOH, CaO
[D] NaNO3, KNO3, CaO
Show Answer
Correct Answer: D [NaNO3, KNO3, CaO]
Notes:
Saltpetre, also spelled Saltpeter, also called Nitre, or Niter, any of three naturally occurring nitrates, distinguished as (1) ordinary saltpetre, or potassium nitrate, KNO3; (2) Chile saltpetre, cubic nitre, or sodium nitrate, NaNO3; and (3) lime saltpetre, wall saltpetre, or calcium nitrate, Ca(NO3)2.
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound.
3. Which of the following is the most active chemically?
[A] Chlorine
[B] Flourine
[C] Lithium
[D] Iodine
Show Answer
Correct Answer: B [Flourine]
Notes:Fluorine is most active because it has the highest electronegativity
4. 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
Show Answer
Correct Answer: C [They easily lose electrons ]
Notes:
Alkali metals have one electron in their valence shell and hence they easily lose or donate electron.
5. The energy required to remove an electron from the outermost shell of an atom in its isolated gaseous state is called?
[A] Electron Affinity
[B] Reducing Potential
[C] Ionization Potential
[D] Shell Potential
Show Answer
Correct Answer: C [Ionization Potential ]
Notes:Ionization potential is the energy required to remove an electron from the outermost shell of an atom in its isolated gaseous state. As we move down the group, ionization potential decreases. As we move across the period, ionization potential increases Electron affinity is the energy released on adding an electron to the outermost shell of an atom in its isolated gaseous state.
6. Which among the following is a Noble Gas?
[A] Nitrogen
[B] Hydrogen
[C] Oxygen
[D] Helium
Show Answer
Correct Answer: D [Helium]
Notes:
The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. This chemical series contains helium, neon, argon, krypton, xenon, and radon.
7. Which among the following would cause the bright red color due to bursting of crackers?
[A] Strontium
[B] Sodium
[C] Sulphur
[D] Magnesium
Show Answer
Correct Answer: A [Strontium ]
Notes:
Generally, strontium carbonate is used for red fireworks; calcium chloride is used in orange fireworks; sodium nitrate is used in yellow fireworks; barium chloride is used in green fireworks; copper chloride is used in blue fireworks. Similarly, some other colors are produced by using mixture of metal salts. For example, purple fireworks are produced by using a mixture of strontium (red) and copper (blue) compounds.
8. 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
Show Answer
Correct 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.
9. Which gas is used in making of Vanaspati ghee from vegetable oils?
[A] N2
[B] NO2
[C] H2
[D] Ne
Show Answer
Correct Answer: C [H2]
Notes:
Vanaspati ghee is manufactured from vegetable oil by a process called ‘hydrogenation’. By passing hydrogen gas. Vegetable Oil contains unsaturated fatty acids; upon hydrogenation it is converted into saturated fatty acids to form vanaspati ghee.
10. Identify the thermosetting plastic from the given options:
[A] Polythene
[B] Bakelite
[C] Polyvincychloride
[D] Casseine
Show Answer
Correct Answer: B [Bakelite ]
Notes:A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin. Bakelite is another name of phenol formaldehyde which is a thermosetting plastic.
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