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 is known as White Vitriol?
[A] Zinc Sulphate
[B] Zinc Chloride
[C] Zinc Phosphate
[D] Zinc oxide
Show Answer
Correct Answer: A [Zinc Sulphate]
Notes:
Zinc sulfate is the inorganic compound with the formula ZnSO4 and historically known as “white vitriol” Zinc sulfate is an inorganic compound and dietary supplement.
2. The easily noticed smell of the LPG gas is because of which among the following?
[A] Butane
[B] Propane
[C] Methane
[D] Ethanethiol
Show Answer
Correct Answer: D [Ethanethiol]
Notes:
Ethanethiol or stench, is a organosulfur compound and is used to add to the otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks.
3. What type of fiber is Rayon considered?
[A] A synthetic fiber
[B] A natural fiber
[C] A semi-synthetic fiber
[D] A synthetic detergent
Show Answer
Correct Answer: C [A semi-synthetic fiber]
Notes:
Rayon is considered a semi-synthetic fiber. It is made by regenerating natural materials into a usable form. Rayon fibers are derived from cellulose obtained from wood or related agricultural products. It was first commercially produced in 1905 by the Swiss firm J. R. Geigy, originally under the name “artificial silk”
4. What is the primary use of Phenolphthalein in chemistry?
[A] A Solvent
[B] A Dye
[C] A Catalyst
[D] A Detergent
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Correct Answer: B [A Dye]
Notes:
Phenolphthalein is commonly employed as a pH indicator in titrations due to its distinct color change in varying pH levels. At pH 8.2, it appears colorless but turns pink as the pH increases to 10. It is not used as a solvent, catalyst or detergent. It also finds applications in forensic science for detecting latent blood stains.
5. Which among the following were not discovered by the time , Mendeleev published his periodic table?
[A] Lathanides
[B] Actinides
[C] Noble Gases
[D] Halogens
Show Answer
Correct Answer: C [Noble Gases]
Notes:
When Mendeleev published his periodic table in 1869, noble gases had not yet been discovered. The first noble gas, argon, was identified in 1894 by Lord Rayleigh and William Ramsay. In contrast, lanthanides and actinides were recognized later, but their existence was inferred from Mendeleev’s predictions. Halogens, including elements like chlorine and iodine, were known prior to Mendeleev’s work.
6. The Potassium graphite and Calcium Graphite can be mostly used as which among the following?
[A] Moderators
[B] Semiconductors
[C] Superconductors
[D] Lubricants
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Correct Answer: C [Superconductors]
Notes:
Potassium graphite and calcium graphite are primarily used as superconductors. Superconductors are materials that can conduct electricity without resistance when cooled below a certain temperature. Graphite, particularly when doped with potassium or calcium, exhibits enhanced superconducting properties. Notably, the discovery of high-temperature superconductors in the 1980s revolutionized the field, leading to applications in magnetic levitation and advanced electronic devices.
7. Which of the following is not an isotope of Hydrogen?
[A] Protium
[B] Para hydrogen
[C] Deuterium
[D] Tritium
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Correct Answer: B [ Para hydrogen]
Notes:
The three most stable isotopes of hydrogen: Protium, Deuterium and Tritium. Para hydrogen is not an isotope of hydrogen. Molecules of hydrogen in which the spins of both the nuclei are in the opposite direction are called Para hydrogen.
8. Which of the following laws states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture?
[A] Raoult’s law
[B] Henry’s law
[C] Graham’s law
[D] Sievert’s law
Show Answer
Correct Answer: A [ Raoult’s law]
Notes:
Raoult’s law states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture.
9. Which of the following chemicals is also known as "sweet oil of vitriol"?
[A] Diethyl ether
[B] Aluminium sulphate
[C] Sulphuric acid
[D] Iron(III) sulphate
Show Answer
Correct Answer: A [ Diethyl ether]
Notes:
Diethyl ether is a colourless, highly volatile & flammable organic compound. It was earlier used for anaesthesia but after the development of non-flammable drugs, its uses as anaesthetic has been reduced.
10. What is the atomic number of Barium?
[A] 54
[B] 56
[C] 58
[D] 60
Show Answer
Correct Answer: B [56]
Notes:
The atomic number of barium is 56.