Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
1. The Alkali metals are called good reducing agents. This implies that__:
[A] They easily capture electrons
[B] They are not stable at room temperature
[C] They easily lose electrons
[D] They don’t act with dilute acids
Show Answer
Correct Answer: C [They easily lose electrons ]
Notes:
Alkali metals have one electron in their valence shell and hence they easily lose or donate electron.
2. Which of the following does not increase when we move from left to right along a period in the periodic table?
[A] Oxidising Power of elements
[B] Electronegativity
[C] Non-metallic Character
[D] Reducing power
Show Answer
Correct Answer: D [Reducing power]
Notes:
The oxidizing power of elements increases on moving left to right along a period in the periodic table. This is because electronegativity and the non-metallic character increases from left to right.
3. What are the main constituents of LPG?
[A] Methane, Hexane, Ethane
[B] Methane, Butane, Propane
[C] Ethane, Pentane, Hexane
[D] Ethane, Methane, Pentane
Show Answer
Correct Answer: B [Methane, Butane, Propane]
Notes:
LPG is composed hydrocarbons containing three or four carbon atoms. The normal components of LPG thus, are propane (C3H8), butane (C4H10) and Methane (CH4). Small concentrations of other hydrocarbons may also be present.
4. When Sulphur is heated with rubber, the process is commonly known as ?
[A] Galvanization
[B] Sulphonation
[C] Vulcanization
[D] Hydrodesulfurization
Show Answer
Correct Answer: C [Vulcanization]
Notes:
Natural rubber becomes soft at high temperature (>335 K) and brittle at low temperatures (<283 k) and shows high water absorption capacity. It is soluble in non-polar solvents and is non-resistant to attack by oxidising agents. To improve upon these physical properties, a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.
In the manufacture of tyre rubber, 5% of sulphur is used as a crosslinking agent
5. Which among following is rich in Ozone?
[A] Stratosphere
[B] Mesosphere
[C] Ionosphere
[D] Troposphere
Show Answer
Correct Answer: A [Stratosphere]
Notes:
The stratosphere is rich in Ozone. The rest of the layers might have ozone to a small extent but not to large extent.
6. Which among the following suspension in water is often called milk of magnesia because of its milk-like appearance?
[A] Magnesium Carbonate
[B] Magnesium Hydroxide
[C] Magnesium Lactate
[D] Magnesium Oxide
Show Answer
Correct Answer: B [Magnesium Hydroxide]
Notes:
Magnesium Hydroxide in water is often called milk of magnesia because of its milk-like appearance. Magnesium hydroxide is the inorganic compound and occurs in nature as the mineral brucite.
7. 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.
8. How many electrons can the s-orbital accommodate?
Show Answer
Correct Answer: B [2]
Notes:
A the s-orbital can accommodate only two electrons, two groups (1 & 2) belong to the s-block of the Periodic Table.
9. Which of the following is a correct statement about minerals and ores?
[A] All minerals are ores
[B] All ores are minerals
[C] Minerals are the native form in which various metals exist
[D] Ores are usually used to extract metals economically
Show Answer
Correct Answer: A [All minerals are ores]
Notes:
All ores are minerals but all minerals are not ores. Minerals are the native form in which various metals exist and ores are those minerals which are used to extract metals economically.
10. Which of the following is correct about Photoelectric effect?
[A] number of electrons ejected is twice the wavenumber of radiation
[B] number of electrons ejected is proportional to the intensity of light
[C] number of electrons ejected is proportional to the duration of light
[D] number of electrons ejected is not dependent on the intensity of light
Show Answer
Correct Answer: B [number of electrons ejected is proportional to the intensity of light]
Notes:
The phenomenon of ejection of electrons from the surface of metal when light of suitable frequency strikes it is called photoelectric effect. The number of electrons ejected is proportional to the intensity or brightness of light.
