Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. A high-refractive-index polymer (HRIP) is a polymer that has a refractive index greater than _?
[A] .50
[B] 1.0
[C] 1.20
[D] 1.50
Show Answer
Correct Answer: D [1.50]
Notes:
A high-refractive-index polymer is a polymer that has a refractive index greater than 1.50. Such materials are required for anti-reflective coating and photonic devices such as light emitting diodes (LEDs) and image sensors.
2. Which among the following is known as Quick Lime?
[A] CaO
[B] CaCO2
[C] Ca(OH)2
[D] CaCl2
Show Answer
Correct Answer: A [CaO]
Notes:
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature.
3. Which compound of mercury is used as antiseptic?
[A] Mercuric sulphide
[B] Mercuric oxide
[C] Mercuric chloride
[D] Mercuric iodide
Show Answer
Correct Answer: C [Mercuric chloride]
Notes:
Mercury chloride (HgCl2) is a highly toxic compound that volatizes slightly at ordinary temperature and appreciably at 100 degrees C. It is corrosive to mucous membranes and used as a topical antiseptic and disinfectant.
4. Identify the Noble Gas from the following options:
[A] Nitrogen
[B] Hydrogen
[C] Oxygen
[D] Helium
Show Answer
Correct Answer: D [Helium]
Notes:
Helium, a noble gas, is the second most abundant element in the universe after Hydrogen. It is colorless, odorless, tasteless, non-toxic, and non-reactive because its outermost electron shell is full with two electrons. This complete outer shell gives it the stability that defines the Noble Gases. Despite its abundance in the universe, Helium is relatively rare on Earth, primarily obtained from natural gas wells.
5. Which among the following was first human-made plastic?
[A] Bakelite
[B] Polyethene
[C] Celluloid
[D] Nylon
Show Answer
Correct Answer: C [Celluloid]
Notes:
The first synthetic plastic was actually celluloid, invented by Alexander Parkes in 1855. Initially, celluloid was primarily used in photographic films. However, it had limitations, not suitable for making containers or electrical insulation. The first genuine plastic, Bakelite, was invented by Leo Baekeland in 1909 and extensively used in various applications, including safely handled autos. World War I significantly contributed to the development of polystyrene and polyvinyl chloride, widely used in plumbing and electrical insulation. Later, in the 1930s, nylon was invented, and by 1950, plastic materials gained immense popularity.
6. Which of the following chemicals is used as a molecular sieve to filter common salts from seawater to produce potable water?
[A] Graphene oxide
[B] Phosgene
[C] Sodium hypochlorite
[D] Calcium carbonate
Show Answer
Correct Answer: A [ Graphene oxide]
Notes:
Graphene oxide is used as a molecular sieve to filter common salts from seawater to produce potable water.
7. Which of the following catalyst is used generally during the hydrogenation of Alkenes?
[A] Platinum
[B] Palladium
[C] Nickel
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Dihydrogen gas adds to alkenes and alkynes in the presence of finely divided catalysts like platinum, palladium or nickel to form alkanes.
8. Which of the following elements have a compound named as Hydrogen peroxide?
[A] Hydrogen, Carbon and Oxygen
[B] Hydrogen only
[C] Hydrogen and Oxygen
[D] Hydrogen, Oxygen and Potassium
Show Answer
Correct Answer: C [Hydrogen and Oxygen]
Notes:
Hydrogen peroxide is a compound of Hydrogen and Oxygen.
9. What is the hemihydrate of calcium sulphate commonly known as?
[A] Gypsum
[B] Plaster of Paris
[C] Chloroform
[D] Limestone
Show Answer
Correct Answer: B [Plaster of Paris]
Notes:
Plaster of Paris is the common name of calcium sulphate hemihydrate because half molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO4.1/2H2O.
10. Which of the following is NOT correct about Ethanol?
[A] It is a good solvent
[B] It gives out hydrogen when reacted with Sodium
[C] It is an odorless liquid
[D] All are correct
Show Answer
Correct Answer: C [It is an odorless liquid]
Notes:
Ethanol is a good solvent and reacts with sodium leading to the evolution of hydrogen. It is a colorless liquid with a slight characteristic odor.
