Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Highest percentage of nitrogen is found in which among the following fertilizers among the given options?
[A] Calcium ammonium nitrate
[B] Ammonium nitrate
[C] Calcium nitrate
[D] Urea
Show Answer
Correct Answer: D [Urea]
Notes:
The agricultural industry widely uses urea, a white crystalline solid containing 46 percent nitrogen as an animal feed additive and fertilizer. Urea has the highest nitrogen content of all solid fertilizers at 46% N.
2. 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
Show Answer
Correct Answer: A [Raise Octane Number ]
Notes:
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.
3. Which among the following is Quick Silver?
[A] Aluminium
[B] Mercury
[C] Lead
[D] Zinc
Show Answer
Correct Answer: B [Mercury]
Notes:
Mercury is a chemical element with the symbol Hg and atomic number 80. The element is also known as quicksilver for its mobility. Mercury is one of the oldest and deadliest poisons, a highly toxic metal mined from a brilliant red ore.
4. How many parts are of other metals in a 17 carat Gold?
[A] 3
[B] 5
[C] 7
[D] 9
Show Answer
Correct Answer: C [7]
Notes:
In 17 carat gold, the composition is 17 parts gold and 7 parts other metals, making it 70.6% gold. The term “carat” refers to the purity of gold, with 24 carats being pure gold. Thus, 17 carat gold contains 7 parts of other metals, which can include copper, silver, or palladium, used to enhance durability and alter color.
5. Consider the following substances:
- Iodine
- Naphthalene
- Camphor
Which of the above substances undergo ‘sublimation’ on heating?
[A] Only 1 and 2
[B] All of them
[C] Only 2 and 3
[D] Only 1 and 3
Show Answer
Correct Answer: B [All of them]
Notes:
Sublimation is a transition from solid to gas, bypassing the liquid phase. Iodine sublimes, producing violet vapors; naphthalene sublimes, hence its use in mothballs; and camphor also sublimes, used in medicinal and aromatic applications. Thus, all three substances exhibit sublimation upon heating, making ‘All of them’ the correct answer.
6. Which of the following is NOT correct about Sodium chloride?
[A] It is a covalent compound
[B] It is also known as common salt
[C] It is also used in de-icing of roadways during snowfall
[D] It is used as a food preservative
Show Answer
Correct Answer: A [It is a covalent compound]
Notes:
Sodium chloride (NaCl) is used as a common salt or table salt for domestic purpose and used as a food preservative. It is an ionic compound. It is also used in de-icing of roadways during snowfall.
7. What is Rose metal?
[A] It is an alloy of Nickel, Tin and Zinc
[B] It is an alloy of Bismuth, Copper and Palladium
[C] It is an alloy of Palladium, Tin and Lead
[D] It is an alloy of Bismuth, Tin and Lead
Show Answer
Correct Answer: D [It is an alloy of Bismuth, Tin and Lead]
Notes:
Rose metal is an alloy of Bismuth, Tin and Lead. It’s a fusible alloy with low melting point commonly used for soldering.
8. What do we call the process that separates a pure solid in the form of its crystals from a solution?
[A] Crystallisation
[B] Sublimation
[C] Chromatography
[D] Distillation
Show Answer
Correct Answer: A [Crystallisation]
Notes:
Crystallisation is a process that separates a pure solid in the form of its crystals from a solution. For example: purification of the salt obtained from sea water.
9. Choose the incorrect statement:
[A] Epsom salt is an ore containing Sodium
[B] Bauxite is an ore of Aluminium
[C] Asbestos is an ore containing Calcium
[D] Milarite mineral contains Nickel
Show Answer
Correct Answer: A [Epsom salt is an ore containing Sodium]
Notes:
Epsom salt is an ore containing Magnesium. It is also known as the heptahydrate sulfate mineral. Its chemical formula is MgSO4·7H2O.
10. What do we call the ratio of number of fission produced by a given generation of neutrons to the number of fission of the preceding generation?
[A] Critical factor
[B] Energy factor
[C] Multiplication factor
[D] Moderation factor
Show Answer
Correct Answer: C [Multiplication factor]
Notes:
The multiplication factor is the ratio of number of fission produced by a given generation of neutrons to the number of fission of the preceding generation.
