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 are the most and the least electronegative elements in the periodic table?
[A] Fluorine and Caesium
[B] Hydrogen and Helium
[C] Carbon and Oxygen
[D] Chlorine and Fluorine
Show Answer
Correct Answer: A [Fluorine and Caesium]
Notes:
Caesium is the least electronegative element in the periodic table and Fluorine is the most electronegative. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.
2. Highest percentage of nitrogen is found in which among the following fertilizers among the given options?
[A] Calcium ammonium nitrate
[B] Ammonium nitrate
[C] Calcium nitrate
[D] Urea
Show Answer
Correct Answer: D [Urea]
Notes:
The agricultural industry widely uses urea, a white crystalline solid containing 46 percent nitrogen as an animal feed additive and fertilizer. Urea has the highest nitrogen content of all solid fertilizers at 46% N.
3. Which among the following substances is most suitable for making Compact Discs?
[A] PVC
[B] Polyethylene
[C] Polyamides
[D] Polycarbonates
Show Answer
Correct Answer: D [Polycarbonates
]
Notes:
Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.
4. Which of the following processes commonly use the method of adsorption?
[A] Scrubbers manufacturing
[B] Purification of solid substances
[C] Chromatography
[D] Purification of liquid substances
Show Answer
Correct Answer: C [Chromatography]
Notes:
Adsorption, the binding of gas or liquid particles to a solid surface, is often used in chromatography – a laboratory technique for the separation of a mixture. This process is critical as it allows the separation of the compounds in the mixture, thereby enabling further analysis or purification. Apart from chromatography, adsorption is also used in scrubbers and purification of solids and liquids.
5. Which among the following is an ionic solid?
[A] Diamond
[B] Dry ice
[C] Table salt
[D] All are ionic solids
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Correct Answer: C [Table salt]
Notes:
One important character of Ionic solids is that they readily get dissolved in water
6. Which among the following is the most important characteristic of Noble metals?
[A] Luster
[B] Non reactive nature
[C] Preciousness
[D] Rare availability
Show Answer
Correct Answer: B [Non reactive nature]
Notes:
Noble metals, such as gold, silver, and platinum, are primarily characterized by their non-reactive nature. This means they resist oxidation and corrosion, making them ideal for use in jewelry and electronics. Unlike base metals, noble metals do not easily form compounds with other elements, which is why they maintain their luster and appearance over time. Their rarity and preciousness are secondary characteristics, but their chemical stability is what truly defines them as noble.
7. Charles Goodyear is known for which of the following ?
[A] Experiments on Rubber Plants
[B] Vulcanization of Rubber
[C] Invention of Radial Tyres
[D] Invention of Artificial Rubber
Show Answer
Correct Answer: B [Vulcanization of Rubber]
Notes:
Charles Goodyear, American inventor of the vulcanization process that made possible the commercial use of rubber. The Goodyear Tire and Rubber Company was posthumously named after him.
8. F block elements in the periodic table which are commonly called Lanthanides have the following atomic numbers:
[A] 57-70
[B] 57-71
[C] 58-71
[D] 58-70
Show Answer
Correct Answer: B [57-71]
Notes:
The correct answer is 2. The lanthanides are a series of 15 elements in the periodic table, from atomic numbers 57 (Lanthanum) to 71 (Lutetium). They are known for their similar properties and are often found together in nature. The range of atomic numbers for lanthanides is 57 to 71, not 57-70 or 58-70.
9. Which among the following will undergo a chemical reaction depending on the pH of the solution?
[A] Calcium Oxide
[B] Zinc Oxide
[C] Ferric Oxide
[D] Ferrous Oxide
Show Answer
Correct Answer: B [Zinc Oxide]
Notes:
Zinc oxide (ZnO) can undergo a chemical reaction depending on the pH of the solution. In acidic conditions, it can react to form zinc ions (Zn²⁺), while in alkaline conditions, it can form zincates. This behavior is due to its amphoteric nature, which allows it to react with both acids and bases. In contrast, calcium oxide (CaO) is basic, ferric oxide (Fe₂O₃) is generally inert in neutral pH, and ferrous oxide (FeO) is less reactive in varying pH levels.
10. 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.