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 oxides cause the Acid rain?
[A] Carbon monoxide and carbon dioxide
[B] Nitrous oxide and sulphur dioxide
[C] Carbon dioxide and nitrous oxide
[D] Sulphur dioxide and carbon monoxide
Show Answer
Correct Answer: B [Nitrous oxide and sulphur dioxide ]
Notes:
Acid rain is caused by nitrous oxides (NOx) and sulfur dioxide (SO2) emissions, which react with water molecules in the atmosphere to form nitric and sulfuric acids. These acids then fall to the ground in rain, snow, fog, or dust particles.
2. Who among the following had given the Atomic Theory?
[A] Benzamin Franklin
[B] Madam curie
[C] Albert Einstien
[D] John Dalton
Show Answer
Correct Answer: D [John Dalton]
Notes:
The correct answer is John Dalton. He proposed the Atomic Theory in the early 19th century, stating that matter is composed of indivisible atoms, each with a specific weight. Dalton’s work laid the foundation for modern chemistry. Notably, he also introduced the concept of atomic weights and was the first to use symbols to represent atoms of different elements.
3. What is the primary event that occurs during an oxidation reaction?
[A] Electrons are gained
[B] Electrons are lost
[C] Protons are gained
[D] Protons are lost
Show Answer
Correct Answer: B [Electrons are lost]
Notes:
Oxidation is a chemical reaction in which an atom, ion, or molecule loses an electron to another substance. So, the correct answer is “Electrons are lost”. This phenomenon is often observed in various chemical and biological systems. Understanding this important process can allow us to gain insights in fields ranging from biology to materials science.
4. Which of the following is not a common use of Graphite?
[A] Manufacturing of electrodes
[B] As a lubricant
[C] Manufacturing of crucibles
[D] In glass cutting
Show Answer
Correct Answer: D [In glass cutting]
Notes:
Graphite is renowned for its conspicuous uses owing to its unique properties like its ability to conduct electricity, which makes it ideal for electrode manufacturing. It’s also used as a lubricant and in the production of crucibles, thanks to its high melting point. However, it isn’t used in glass cutting.
5. What are Sodium Alkyl Sulphate and Benzene Sulphate examples of?
[A] Explosives
[B] Insecticides
[C] Fungicides
[D] Synthetic Detergents
Show Answer
Correct Answer: D [Synthetic Detergents]
Notes:
Sodium Alkyl Sulphate and Benzene Sulphate are typical examples of Synthetic Detergents. Synthetic detergents are man-made cleansing agents that function similarly to soap. These compounds were developed during World War II when a shortage of natural oils led to a search of alternative substances. The advanced features of synthetic detergents include improved cleansing efficacy, resistance to water hardness, and the ability to function in acidic conditions.
6. Which among the following gas is used in Balloons?
[A] Hydrogen
[B] Helium
[C] Nitrogen
[D] Oxygen
Show Answer
Correct Answer: B [Helium]
Notes:
The correct answer is Helium. Helium is a non-flammable, lighter-than-air gas, making it safe for use in balloons. Unlike hydrogen, which is highly flammable and poses explosion risks, helium is inert and does not react with other substances. Helium is the second most abundant element in the universe, primarily produced through nuclear fusion in stars. It was first discovered in the sun before being found on Earth.
7. Under standard conditions, which of the following is the most stable form of carbon?
[A] Charcoal
[B] Graphite
[C] Diamond
[D] Amorphous Carbon
Show Answer
Correct Answer: B [Graphite]
Notes:
Under standard conditions, Graphite is the most stable form of carbon. It is commonly used in pencils and lubricants due to its layered structure. These layers can move over each other, making graphite soft and slippery. Besides Graphite, other forms of carbon are diamond, charcoal, and amorphous carbon, each with unique properties and applications.
8. Pyrolusite, Braunite, Psilomelane, Rhodochrosite are the ores of which among the following metals?
[A] Manganese
[B] Aluminium
[C] Copper
[D] Manganese and Copper
Show Answer
Correct Answer: A [Manganese]
Notes:
Pyrolusite, Braunite, Psilomelane, and Rhodochrosite are all ores of Manganese. Pyrolusite is one of the most important ores due to its high manganese content. Braunite, although a significant ore, its manganese content is less than Pyrolusite. Psilomelane and Rhodochrosite also contribute as minor ores.
9. The colors in the fine cut diamond are because of which among the following?
[A] Variance in transparency of diamond
[B] Variance in index of refraction
[C] Presence of Impurities
[D] Existence of definite planer layers
Show Answer
Correct Answer: C [Presence of Impurities]
Notes:
Pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice is exceptionally strong and only atoms of nitrogen, boron and hydrogen can be introduced into diamond during the growth at significant concentrations (up to atomic percents). Nitrogen gives yellowish color while the Boron gives bluish color.
10. The synthetic rubber Buna is obtained from the reaction of an unsaturated hydrocarbon with ___:
[A] Sodium
[B] Magnesium
[C] Potassium
[D] Lithium
Show Answer
Correct Answer: A [Sodium]
Notes:
Buna-S is a synthetic rubber formed by co-polymerization of a mixture of 1:3 butadiene and styrene. It is obtained from Sodium.