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 of the following is the poorest conductor of heat in comparison to other options?
[A] Silver
[B] Copper
[C] Lead
[D] Mercury
Show Answer
Correct Answer: C [ Lead ]
Notes:
Silver is best conductor of heat while among metals lead is poorest conductor of heat. Cooper and aluminum are good conductor while mercury is a poor conductor.
2. Dalton’s name is associated with which of the following terms?
[A] Electron
[B] Proton
[C] Atom
[D] Neutron
Show Answer
Correct Answer: C [Atom]
Notes:
John Dalton introduced the atomic theory into chemistry. The main points of Dalton’s atomic theory are (1) Elements are made of extremely small particles called atoms. (2) Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.(3) Atoms cannot be subdivided, created or destroyed. (4) Atoms of different elements combine in simple whole-number ratios to form chemical compounds. (5) In chemical reactions, atoms are combined, separated or rearranged.
3. 2,4-D, which is sold as a weed killer of the broad-leaved weeds is a synthetic version of __:
[A] Auxin Hormone
[B] Cytokinin Hormone
[C] Xylitol
[D] None of them
Show Answer
Correct Answer: A [Auxin Hormone ]
Notes:
2,4-dichlorophenoxyacetic acid (2,4-dichlorophenoxyethanoic acid) is a synthetic auxin frequently used as a weed killer of broad-leaved weeds. When two herbicides 2,4,5-T and 2,4-D and mixed in equal parts, it is called Agent Orange, which was used by US in Vietnam war.
4. Buckeyballs are basically the allotropes of _________?
[A] Carbon
[B] Sulfur
[C] Phosphorus
[D] Calcium
Show Answer
Correct Answer: A [Carbon]
Notes:
Buckeyballs, or fullerenes, are allotropes of carbon. Discovered in 1985, they consist of 60 carbon atoms arranged in a spherical shape, resembling a soccer ball. This unique structure contributes to their remarkable properties, including high strength and electrical conductivity. Fullerenes are part of a broader class of carbon allotropes, which also includes graphite and diamond.
5. If a baby diaper is subjected to different solutions, which of the following will it absorb the maximum quantity of?
[A] Distilled Water
[B] Drinking Water
[C] Hard Water
[D] Urine
Show Answer
Correct Answer: A [Distilled Water]
Notes:
A baby diaper can absorb the maximum quantity of distilled water as it lacks impurities such as minerals and ions that are present in other type of water. The absorbent materials in diapers, often polymers called sodium polyacrylate, can hold up to 30 times their weight in distilled water, making them highly efficient.
6. Which among the following will emit maximum mass of carbon dioxide , when the same quantity is burnt of all of them?
[A] Kerosene
[B] Natural Gas
[C] Gasoline
[D] Propane
Show Answer
Correct Answer: A [Kerosene]
Notes:
The carbon content of Kerosene is higher than the other fuels mentioned in the option, that is why it will emit maximum mass of carbon dioxide, when the same quantity is burnt.
7. Why most of the aromatic hydrocarbons burn with a sooty flame?
[A] Because the carbon-hydrogen ratio in aromatic compounds is high
[B] Because of the presence of the strong carbon-carbon bonds
[C] Because, hydrocarbons are unsaturated
[D] Because the carbon-hydrogen ratio in aromatic compounds is low
Show Answer
Correct Answer: A [ Because the carbon-hydrogen ratio in aromatic compounds is high]
Notes:
Because the carbon-hydrogen ratio in aromatic compounds is high.
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 mixture can be separated by Fractional distillation method?
[A] Air
[B] Crude oil
[C] Chlorosilanes
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Fractional distillation method is used to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K. example: Air, crude oil, chlorosilanes etc.
10. What is an alloy of mercury with some other metal generally known as?
[A] Galinston
[B] Amalgam
[C] Megalium
[D] Yellow metal
Show Answer
Correct Answer: B [Amalgam]
Notes:
Amalgam is the general name given to an alloy of mercury with some other metal. It can be a solid, liquid or a soft paste depending on the composition of the constituents.
