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. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
1. Which of the following are the most and the least electronegative elements in the periodic table?
[A] Fluorine and Caesium
[B] Hydrogen and Helium
[C] Carbon and Oxygen
[D] Chlorine and Fluorine
Show Answer
Correct Answer: A [Fluorine and Caesium]
Notes:
Caesium is the least electronegative element in the periodic table and Fluorine is the most electronegative. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.
2. Which of the following is not a correct statement about Bitumen?
[A] It’s a mixture of highly condensed polycyclic aromatic compounds
[B] Its is soluble in Carbon Disulphide
[C] SARA analysis is used to determine bitumen chemistry
[D] All of above are correct statements
Show Answer
Correct Answer: D [ All of above are correct statements ]
Notes:
Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, soluble in carbon disulfide and composed of highly condensed polycyclic aromatic hydrocarbons.
3. 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.
4. After a nuclear disaster, the Strontium-90 becomes an health issue of great concern. What is the major concern about this particular isotope?
[A] Strontium-90 gets deposited in the Red Blood Cells and causes Blood Cancer
[B] Strontium-90 gets deposited in the Liver cells and causes Liver Cirrhosis
[C] Strontium-90 gets deposited in bones and bone marrow and causes cancer
[D] None of the above is a correct statement
Show Answer
Correct Answer: C [ Strontium-90 gets deposited in bones and bone marrow and causes cancer]
Notes:
Strontium-90 is a “bone seeker” that exhibits biochemical behaviour similar to calcium, the next lighter Group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70–80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marrow, with the remaining 1% remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukaemia.
5. Consider the following:
- Atomic number
- Atomic mass
- Number of protons
- Number of neutrons
Which among the above is / are same for each of C-12, C-13 and C-14?
[A] 1 & 3
[B] 2 & 4
[C] 2 & 3
[D] 1 & 4
Show Answer
Correct Answer: A [ 1 & 3]
Notes:
Isotopes contain equal numbers of protons but different numbers of neutrons.
6. Which of the following can be used to treat alkali soils?
1. Pyrite
2. Gypsusm
3. Organic Manure
Select the correct option from the codes given below:
[A] 1 & 2
[B] 2 & 3
[C] 1, 2 & 3
[D] None of them
Show Answer
Correct Answer: C [ 1, 2 & 3]
Notes:
All viz. Pyrite, Gypsum and Organic Manure can be used for reclaimation of Alkali soil.
7. Consider the following chemicals:
- Copper sulfate
- Ozone
- Hydrogen peroxide
- Fluoride
Which of the above are used in chemical treatment process of drinking water?
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1, 2 & 3
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: D [ 1, 2, 3 & 4]
Notes:
Copper sulphate is used as an algicide for algal growth is copper sulfate. Ozone or Hydrogen peroxide is added to oxidise organic compounds, and thus reduce the amount of coagulant required. Fluoride is a naturally occurring mineral in water and many foods. In addition, fluoride is intentionally added to the public water supplies, because it has been demonstrated that communities with fluoride added to their water supplies have significantly reduced incidence of tooth decay in children. Fluoride makes teeth more resistant to the acid formed by bacteria in the mouth by preventing these acids from removing essential minerals from the tooth surface. Fluoride also helps to repair damaged tooth enamel.
8. Which of the following is / are correct statements?
- The carbon content in Cast iron is less than that in Pig Iron
- Wrought iron has lower carbon content than both the Cast Iron and Pig Iron
Select the correct option from the codes given below:
[A] Only 1 is correct
[B] Only 2 is correct
[C] Both 1 & 2 are correct
[D] Neither 1 nor 2 is correct
Show Answer
Correct Answer: C [ Both 1 & 2 are correct]
Notes:
The immediate product of the Iron alloy found in mines is “Pig iron”. Pig Iron has a very high Carbon Content (3.5-4.5%). So it is Brittle, Non-malleable and used only in limited applications. Iron alloy which has impurity more than 2.1% but less than the Pig Iron is called “Cast Iron”. They are mostly brittle but there are Malleable Cast Irons. The Cast Iron because of more impurities has a lower melting point. Historically cast Iron has been used in “Bridge making” all over the word. The famous “Iron Bridge” of England is made up of Cast Iron. “Wrought iron” has very low carbon content. It is also known as “Slag’. When it is bent to the point of breaking, it gives texture which resembles wood. Wrought Iron was earlier known as “Pure Iron”, but not now because; now the Iron, which has less than 0.008% impurity is considered to be commercially pure. The “Eiffel Tower “is made up of Wrought Iron.
9. Which of the following get corroded by open air due to oxidation?
- Iron
- Copper
- Zinc
- Aluminium
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1, 2 & 3
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: D [1, 2, 3 & 4]
Notes:
All of them are subject to corrosion. Kindly note that the output of aluminum corrosion is aluminum oxide, which is a very hard material. Thus, it actually protects the aluminum from further corrosion and that is why Aluminium is called corrosion resistant.
10. Which of the following states of matter has the weakest Intermolecular forces?
[A] Solids
[B] Liquids
[C] Gases
[D] It is same in solids, liquids and gases
Show Answer
Correct Answer: C [Gases]
Notes:
The three states of matter varies from each other due to the following factors. (1) The different magnitudes of the interatomic and intermolecular forces. (2) The extent of random thermal motion of atoms and molecules of a substance (which depends upon temperature). The Intermolecular force is strongest in solids and weakest in gases.
