Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Potassium permanganate is used to purify water. Which among the following properties of Potassium permanganate helps in this work?
[A] sterilizing
[B] oxidizing
[C] reducing
[D] leaching
Show Answer
Correct Answer: B [oxidizing]
Notes:
Potassium permanganate is a point-of-entry treatment method that oxidizes dissolved iron, manganese, and hydrogen sulfide into solid particles that are filtered out of the water. It can also be used to control iron bacteria growth in wells.
2. Which among the following is major component of Gobar Gas?
[A] Butane
[B] Ethane
[C] Propane
[D] Metahne
Show Answer
Correct Answer: D [Metahne]
Notes:
Gobar Gas or Biogas is mostly methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes.
3. 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.
4. 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.
5. Flint, which was used by the prehistoric man to make tools is a __?
[A] Igneous rock
[B] Sedimentary rock
[C] Metamorphic rock
[D] None of the above
Show Answer
Correct Answer: B [ Sedimentary rock]
Notes:
Flint is a sedimentary rock. It’s a type of microcrystalline quartz in the chert family. Flint is known for its sharp edges and ability to be easily flaked into various shapes. It was widely used by early humans to make a variety of tools, including: Knives, Scrapers, Points, Axe-heads, Hammers, Choppers. Flint is often found along streams and beaches. It’s close behind diamond in hardness and fractures easily to give razor sharp edges.
6. Which of the following chemicals is also known as “Chinese snow”?
[A] Silver iodide
[B] Potassium nitrate
[C] Ammonium chloride
[D] Sodium phosphate
Show Answer
Correct Answer: B [ Potassium nitrate]
Notes:
Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpetre or saltpetre. It is also known as “Chinese snow”. Major uses of potassium nitrate are in fertilizers, rocket propellants and fireworks.
7. Which of the following is / are correct statement(s) about Gypsum?
[A] It’s a mineral composed of calcium sulfate dihydrate
[B] It is a soft mineral
[C] It is commonly added to saline soils to reduce salinity
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Gypsum is a mineral composed of calcium sulfate dihydrate. It’s a soft mineral and colorless to white in color. It is commonly added to saline soils to reduce salinity and also used in wallboard (drywall) and plaster of paris.
8. What do we call the difference between the initial mass energy and the total mass energy of the decay products in a radioactive decay?
[A] entropy
[B] disintegration energy
[C] alpha energy
[D] integration energy
Show Answer
Correct Answer: B [disintegration energy]
Notes:
The disintegration energy or the Q-value of a nuclear reaction is the difference between the initial mass energy and the total mass energy of the decay products.
9. What is the period and group number of Silicon (Z=14) in the periodic table?
[A] 2nd Period, 4th Group number
[B] 2nd Period, 14th Group number
[C] 3rd Period, 4th Group number
[D] 3rd Period, 14th Group number
Show Answer
Correct Answer: D [3rd Period, 14th Group number]
Notes:
Silicon has an atomic number 14 and the outer electronic configuration is 3s2 3ps2. It is placed at the 3rd Period and 14th Group number.
10. What are the products of the reaction when metal carbonate reacts with an acid?
[A] Salt and Hydrogen
[B] Carbon dioxide
[C] Salt, Carbon dioxide and water
[D] Salt, Carbon dioxide and Hydrogen
Show Answer
Correct Answer: C [Salt, Carbon dioxide and water]
Notes:
All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt, carbon dioxide and water. Limestone, chalk and marble are different forms of calcium carbonate.
