Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. White Phosphorous is represented by which among the following symbols?
[A] P1
[B] P2
[C] P3
[D] P4
Show Answer
Correct Answer: D [P4]
Notes:
The most important form of elemental phosphorus from the perspective of applications and chemical literature is white phosphorus. It consists of tetrahedral P4 molecules, in which each atom is bound to the other three atoms by a single bond. This P4 tetrahedron is also present in liquid and gaseous phosphorus up to the temperature of 800 °C when it starts decomposing to P2 molecules
2. Which among the following groups is characteristic to alcohols?
[A] OH group
[B] COOH group
[C] COO group
[D] CO group
Show Answer
Correct Answer: A [OH group]
Notes:
Alcohols are organic compounds characterized by the presence of a hydroxyl group, denoted as -OH. This group consists of one oxygen atom bonded to a hydrogen atom. Due to the presence of the hydroxyl group, alcohols exhibit unique properties, such as the ability to form hydrogen bonds, making them polar. Alcohols are distinct from carboxylic acids (COOH), carbonates (COO), and carbonyl group compounds (CO).
3. How does the Isotope of Iodine, Iodine-135 plays an important role in Nuclear Power Generation?
[A] It is used as a fuel supplement in some of the modern Nuclear Reactors
[B] It is a bi-product of Nuclear Reaction which kills the neutrons and this inhibits the power formation
[C] It is a moderator used actively in the Nuclear Reactors
[D] It is an experimental substance for Nuclear Fusion
Show Answer
Correct Answer: B [It is a bi-product of Nuclear Reaction which kills the neutrons and this inhibits the power formation]
Notes:
Iodine-135 is a important by-product of nuclear fission, particularly in reactors using uranium fuel. It has a high neutron capture cross-section, meaning it effectively absorbs neutrons, which can inhibit the fission process and reduce reactor power output. This property makes it crucial for managing reactor control and safety, as its presence can lead to a phenomenon known as “neutron poison,” affecting the overall efficiency of the nuclear reaction.
4. Haber Process is used to produce which among the following?
[A] Potash
[B] Ammonia
[C] Urea
[D] Nitrates
Show Answer
Correct Answer: B [Ammonia]
Notes:
The Haber Process is an industrial method for synthesizing ammonia from nitrogen and hydrogen gases. Developed by Fritz Haber and Carl Bosch in the early 20th century, it operates under high pressure and temperature, using an iron catalyst. Ammonia produced is crucial for fertilizers, supporting global agriculture. The process importantly increased food production, earning Haber the Nobel Prize in Chemistry in 1918.
5. Aluminum is getting popular worldwide today as a “Green Metal”. Which among the following properties of Aluminum makes it a Green Metal?
[A] Aluminum has been providing a replacement of wood for saving forests and contributes in environment protection
[B] Aluminum is a light metal and it is resistant to corrosion
[C] Aluminum has fairly high rate of recycling and it can be re-used repeatedly without its quality deteriorating
[D] The lands after the Bauxite mining can be restored very quickly and easily
Show Answer
Correct Answer: C [Aluminum has fairly high rate of recycling and it can be re-used repeatedly without its quality deteriorating]
Notes:
Aluminum is considered a “Green Metal” primarily due to its high recycling rate. Approximately 75% of all aluminum ever produced is still in use today, as it can be recycled indefinitely without losing quality. This process saves energy—recycling aluminum uses about 95% less energy than producing new aluminum from bauxite ore. Additionally, recycling reduces greenhouse gas emissions and conserves natural resources, making aluminum a sustainable choice in various applications.
6. Which among the following minerals is also known as Horn Silver?
[A] Silver Iodide
[B] Silver Chroride
[C] Zinc Phosphate
[D] Silver Sulphide
Show Answer
Correct Answer: B [Silver Chroride]
Notes:
Chlorargyrite is the mineral form of silver chloride (AgCl). It is also known as cerargyrite and, when weathered by desert air, as horn silver. Silver chloride is formed by the disappearance of the initial silver oxide layer.
7. Which of the following chemicals is resposible for temporary acid rain in colder regions?
[A] Hydrogen chloride
[B] Sulphur dioxide
[C] Nitric acid
[D] Nitrogen oxides
Show Answer
Correct Answer: A [ Hydrogen chloride]
Notes:
Hydrogen chloride gas released from volcanic eruption is responsible for temporary acid rain in colder regions.
8. Which of the following is NOT correct about Phosphine?
[A] The chemical formula is PH3
[B] The electronic structure is like Ammonia
[C] It is odorless
[D] it is used as a dopant in semiconductor industries
Show Answer
Correct Answer: C [It is odorless]
Notes:
Phosphine is PH3. The electronic structure of Phosphine (pyramidal structure) is like Ammonia. It is a colourless gas and has a spoiled fish smell. It is used as a dopant in semiconductor industries.
9. Which of the following is the composition of vinegar?
[A] 65-75% solution of acetic acid in water
[B] 45-60% solution of acetic acid in water
[C] 28-35% solution of acetic acid in water
[D] 5-8% solution of acetic acid in water
Show Answer
Correct Answer: D [5-8% solution of acetic acid in water]
Notes:
5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles
10. 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.
