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 among the following methods can be used to remove the permanent hardness in water due to calcium or magnesium sulphates?
[A] Sulphonate method
[B] Nitrate method
[C] Zeolite method
[D] None of these
Show Answer
Correct Answer: C [Zeolite method ]
Notes:
Zeolite is hydrated Sodium Alumino-silicate capable of exchanging reversible Sodium ions for hardness producing ions in water. It is also use as softening of water. It is used to remove the permanent hardness in water due to Calcium or Magnesium sulphates.
2. Which of the following is a thermosetting plastic?
[A] Polythene
[B] Bakelite
[C] Polyvinyl chloride
[D] Casseine
Show Answer
Correct Answer: B [Bakelite]
Notes:
Bakelite is a thermosetting plastic formed from phenol and formaldehyde, used in electrical insulators and cookware handles. Unlike thermoplastics, it hardens irreversibly when heated and cannot be remolded. It was the first synthetic plastic, invented by Leo Baekeland in 1907.
3. Which among the following is the correct decreasing of bio elements in Human Body?
[A] oxygen, hydrogen, Carbon, nitrogen, calcium, and phosphorus
[B] oxygen, carbon, nitrogen, hydrogen, calcium, and phosphorus
[C] oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus
[D] carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus
Show Answer
Correct Answer: C [oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus ]
Notes:
In the human body the most common bio-elements (in decreasing order of occurrence) are oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Other bio-elements include sodium, potassium, magnesium, and copper.
4. 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.
5. Which among the following is the most abundant organic compound in nature?
[A] Glucose
[B] Fructose
[C] Sucrose
[D] Cellulose
Show Answer
Correct Answer: D [Cellulose]
Notes:
Cellulose is the most abundant organic compound in nature. It is the main constituent of plant fiber. Plants contain on average 33% cellulose, and cotton is the purest form at 90%. Chitin is the second most abundant organic compound in nature.
6. The primary part of Liquefied Petroleum Gas LPG is ______?
[A] Butane
[B] Methane
[C] Propane
[D] Butane or Propane
Show Answer
Correct Answer: D [Butane or Propane]
Notes:
LPG consists mainly of propane, propylene, butane, and butylene in various mixtures. The primary gas can be either Propane or Butane.
7. Which among the following is the main constituent of vegetable oil and animal fats?
[A] Glycogen
[B] Triglyceride
[C] Galactose
[D] Diglyceride
Show Answer
Correct Answer: B [Triglyceride]
Notes:
The main constituent of vegetable oil and animal fats is triglyceride. Triglycerides are composed of three fatty acids linked to a glycerol molecule. They are the most common type of fat found in the body and serve as a major energy source. In fact, triglycerides account for about 95% of the fats in the human diet.
8. Which among the following alkane has largely replaced the ozone layer-depleting halomethanes in household refrigerators and freezers?
[A] Methane
[B] Propane
[C] Butane
[D] Ethane
Show Answer
Correct Answer: C [Butane]
Notes:
Isobutane, which is known in the industry as R600A has been used in several domestic refrigerators in recent times because it is an excellent refrigerant and non-ozone depleting substance with low global warming potential. The only drawback is that it is highly inflammable.
9. Consider the following substances:
- Iodine
- Napthalene
- Camphor
Which of the above substances undergo ‘sublimation’ on heating?
[A] 1 and 2
[B] 1 and 3
[C] 2 and 3
[D] All of them
Show Answer
Correct Answer: D [All of them]
Notes:Sublimation is the process where a solid turns directly into a gas without passing through the liquid phase.
- Iodine: Sublimes at about 113.7°C, releasing purple vapors.
- Naphthalene: Sublimes at around 80°C, commonly used in mothballs.
- Camphor: Sublimes at approximately 175°C, used in medicinal and aromatic applications.
All three substances can undergo sublimation upon heating, making the correct answer “All of them.”
10. Why most of the aromatic hydrocarbons burn with a sooty flame?
[A] Because the carbon-hydrogen ratio in aromatic compounds is high
[B] Because of the presence of the strong carbon-carbon bonds
[C] Because, hydrocarbons are unsaturated
[D] Because the carbon-hydrogen ratio in aromatic compounds is low
Show Answer
Correct Answer: A [ Because the carbon-hydrogen ratio in aromatic compounds is high]
Notes:
Because the carbon-hydrogen ratio in aromatic compounds is high.
