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
31. What do we call the compounds of carbon having double or triple bonds between the carbon atoms?
[A] Saturated carbon compounds
[B] Unsaturated carbon compounds
[C] Fullerenes
[D] None of the above
Show Answer
Correct Answer: B [Unsaturated carbon compounds]
Notes:
The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated carbon compounds.
32. Who among the following conceived the first recognizable periodic table of chemical elements?
[A] Marie Skłodowska Curie
[B] Dmitri Mendeleev
[C] John Dalton
[D] Amedeo Avogadro
Show Answer
Correct Answer: B [Dmitri Mendeleev]
Notes:
The first periodic table which organizes all chemical elements by the number of protons in a given atom and other properties was developed by Russian scientist Dmitry Mendeleev in 1869. On the occasion of the 150th Anniversary of the inception of the periodic table, 2019 is being celebrated as International Year of the Period Table of Chemical Elements by UNESCO.
33. Which of the following metal is the main constituent in Pewter alloy?
[A] Lead
[B] Zinc
[C] Tin
[D] Iron
Show Answer
Correct 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..
34. Which of the following is correct?
[A] A colloidal solution is a heterogeneous mixture
[B] A colloidal solution is a homogeneous mixture
[C] The particles of a colloidal solution cannot scatter beam of light
[D] None of the above
Show Answer
Correct Answer: A [A colloidal solution is a heterogeneous mixture]
Notes:
Due to the relatively smaller size of particles, as compared to that of a suspension, the mixture appears to be homogeneous. But actually, a colloidal solution is a heterogeneous mixture. The particles can easily scatter a beam of visible light.
35. Which of the following is correct about Manganin?
[A] It is an alloy of copper, manganese and nickel
[B] It has virtually zero temperature coefficient of resistance
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
Manganin is an alloy of copper, manganese and nickel. It is used in the manufacture of resistors due to its virtually zero temperature coefficient of resistance.
36. Which of the following is the correct order of the decreasing order of abundance of the elements in earth’s crust?
[A] Iron > Silicon > Oxygen >Aluminium
[B] Oxygen > Silicon > Aluminium > Iron
[C] Oxygen> Iron > Aluminium > Silicon
[D] Iron > Aluminium > Silicon > Oxygen
Show Answer
Correct Answer: B [Oxygen > Silicon > Aluminium > Iron]
Notes:
Oxygen is the most abundant element in the earth’s crust followed by Silicon, Aluminium and Iron. It comprises almost half of the mass of the earth’s crust.
37. What do we call the process of converting an ore into its oxide by heating it in a limited supply of air below its melting point?
[A] Roasting
[B] Calcination
[C] Leaching
[D] Liquation
Show Answer
Correct Answer: B [Calcination]
Notes:
Calcination is the process of converting an ore into its oxide by heating it in a limited supply of air or in absence of air, below its melting point. It is used to convert the concentrated ore to its oxide.
38. Bayer process is related to which of the following?
[A] production of Copper oxide
[B] production of Alumina
[C] production of Zinc oxide
[D] production of Silicon dioxide
Show Answer
Correct Answer: B [production of Alumina]
Notes:
The Bayer process is the industrial process of refining bauxite to produce alumina (aluminium oxide). In this process, Alumina is separated from the bauxite ore by using a hot solution of caustic soda (sodium hydroxide) and lime (calcium oxide).
39. Which of the following quantum number is also known as orbital angular momentum?
[A] Principal quantum number
[B] Azimuthal quantum number
[C] Magnetic quantum number
[D] Electron spin quantum number
Show Answer
Correct Answer: B [Azimuthal quantum number]
Notes:
Azimuthal quantum number is also known as orbital angular momentum or subsidiary quantum number. It is represented by ‘l’.
40. Which of the following quantum numbers give information about the spatial orientation of the orbital with respect to standard set of co-ordinate axis?
[A] Azimuthal quantum number
[B] Principal quantum number
[C] Magnetic quantum number
[D] Electron spin quantum number
Show Answer
Correct Answer: C [Magnetic quantum number]
Notes:
Magnetic quantum number gives information about the spatial orientation of the orbital with respect to standard set of co-ordinate axis.
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