Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Dalton’s name is associated with which of the following terms?
[A] Electron
[B] Proton
[C] Atom
[D] Neutron
Show Answer
Correct Answer: C [Atom]
Notes:
John Dalton introduced the atomic theory into chemistry. The main points of Dalton’s atomic theory are (1) Elements are made of extremely small particles called atoms. (2) Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.(3) Atoms cannot be subdivided, created or destroyed. (4) Atoms of different elements combine in simple whole-number ratios to form chemical compounds. (5) In chemical reactions, atoms are combined, separated or rearranged.
2. Which among the following substances is most suitable for making Compact Discs?
[A] PVC
[B] Polyethylene
[C] Polyamides
[D] Polycarbonates
Show Answer
Correct Answer: D [Polycarbonates
]
Notes:
Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.
3. Calamine is an ore of which among the following?
[A] Zinc
[B] Copper
[C] Mercury
[D] Iron
Show Answer
Correct Answer: A [Zinc]
Notes:
Calamine is an ore that contains zinc carbonate along with impurities like iron oxide. Through smelting, the zinc carbonate in calamine can be reduced to extract pure zinc metal. Other common zinc ores are sphalerite (zinc sulfide) and smithsonite (zinc carbonate). So calamine is considered a zinc ore due to its zinc carbonate content.
4. Galena & Litharge are ores of which of the following metals?
[A] Mercury
[B] Zinc
[C] Copper
[D] Lead
Show Answer
Correct Answer: D [Lead]
Notes:
Galena and litharge are ores of lead. Galena is the most common ore of lead. It is the natural mineral form of lead (II) sulphid. Litharge is a secondary mineral that forms from the oxidation of galena ores. It is one of the natural mineral forms of Lead(II) oxide.
5. Consider the following:
- Cinnabar is also known as mercurblende
- The color of Cinnabar varies from dull grey to bright green
- Cinnabar is the most common source ore for refining elemental mercury
- Cinnabar is the historic source for the brilliant blue pigment termed azure
Which of the statements given above are correct?
[A] Only 1 and 3
[B] Only 2 and 4
[C] 1, 3 and 4
[D] All Four
Show Answer
Correct Answer: A [Only 1 and 3]
Notes:
Cinnabar, also known as mercurblende, is indeed the most common ore source for refining elemental mercury. However, its color range runs from scarlet to brick-red, not grey to green. It is known for providing the brilliant red or scarlet pigment known as vermilion, not a blue pigment.
6. The chemical oxygen demand COD test is commonly used to measure which of the following?
[A] amount of organic compounds in water
[B] amount of oxygen in water
[C] amount of oxygen in a chemical
[D] amount of oxygen used in a oxygenation process
Show Answer
Correct Answer: A [amount of organic compounds in water]
Notes:
chemical oxygen demand is a measure of water quality and is amount of organic pollutants found in surface water. Potassium permanganate has been used for many years to measure COD
7. Ilmenite, found in Indian coastal sands, is an ore of which element?
[A] Tungsten
[B] Titanium
[C] Gallium
[D] Tin
Show Answer
Correct Answer: B [Titanium]
Notes:
Ilmenite is a titanium-iron oxide mineral with the formula FeTiO3. India holds about 37% of global ilmenite reserves, primarily along the peninsular coastal regions. Ilmenite is the primary source of titanium, used in aerospace, chemical, and medical industries. The Geological Survey of India ranks ilmenite among the most abundant heavy minerals in Indian beach placers. Titanium extraction from ilmenite is commercially viable.
8. Which of the following is the softest metal?
[A] Cesium
[B] Lead
[C] Gold
[D] Silver
Show Answer
Correct Answer: A [ Cesium]
Notes:
Cesium is extremely reactive metal. It reacts with water even at −116 °C (−177 °F). It is the least electronegative element. Cesium is also the softest known metal. It is so soft that it can be cut with a butter knife.
9. Which of these is NOT an allotropic form of carbon?
[A] Diamond
[B] Graphite
[C] Fullerene
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
Carbon exhibits many allotropic forms; both crystalline as well as amorphous. Diamond and graphite are two well-known crystalline forms of carbon. In 1985, third form of carbon known as fullerenes was discovered.
10. Which of the following is NOT correct about Alkynes?
[A] They contain at least two triple bond between two carbon atoms
[B] The number of hydrogen atoms is less in alkynes as compared to alkenes
[C] The general formula of Alkynes is CnH2n–2
[D] All are correct
Show Answer
Correct Answer: A [They contain at least two triple bond between two carbon atoms]
Notes:
Alkynes contain at least one triple bond between two carbon atoms. The number of hydrogen atoms is less in alkynes as compared to alkenes or alkanes. Their general formula is CnH2n–2.
