Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. A Gold Ring which is 50% pure. Its purity can be alternatively shown as __:
[A] 18 Carat
[B] 18 Karat
[C] 12 Carat
[D] 12 Karat
Show Answer
Correct Answer: D [ 12 Karat ]
Notes:
The carat is the common unit used to describe the mass of a gem. A 1-carat diamond, for example, has a mass of 0.20 g. The karat is the common unit used to describe the purity of a precious metal, such as gold. A 24-karat gold ring is as pure as can be. A gold ring that is 50 % pure is 12 karat.
2. Which among the following is popularly called Hypo?
[A] Silver Bromide
[B] Silver nitrate
[C] Sodium thiosulphate
[D] Sodium phosphate
Show Answer
Correct Answer: C [Sodium thiosulphate ]
Notes:
Sodium thiosulfate is an important inorganic salt with several medical uses. It is also called sodium hyposulfite or ‘hypo’. It is used in several pharmaceutical preparations and also has various medical properties.
3. Which of the following type of Coal has maximum carbon content?
[A] Peat
[B] Lignite
[C] Antharacite
[D] Bituminious
Show Answer
Correct Answer: C [Antharacite]
Notes:
Anthracite, often referred to as hard coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
4. Which of the following is the correct term used to describe Graphite, Carbon and Diamonds?
[A] Isotopes
[B] Isomers
[C] Isotones
[D] Allotropes
Show Answer
Correct Answer: D [Allotropes]
Notes:
Allotropes refer to two or more different physical forms in which an element can exist. The property is due to different ways atoms bond together. The most common instance is the element carbon, which exists in several different forms, including diamond, graphite, and fullerenes, making it an allotropic element. It’s crucial to note that allotropy applies to elements, not compounds.
5. According to Avogadro’s hypothesis, equal volumes of gases contain equal number of?
[A] Atoms
[B] Molecules
[C] Particles
[D] Electrons
Show Answer
Correct Answer: B [Molecules]
Notes:
Avogadro’s hypothesis was proposed by Amedeo Avogadro in 1811. It states that equal volumes of all gases, at the same temperature and pressure, contain equal numbers of molecules. Avogadro’s number is defined as 6.022×10^23 molecules per mole. This hypothesis was crucial for determining molecular weights and led to the development of the ideal gas law.
6. Which among the following is an ionic solid?
[A] Diamond
[B] Dry ice
[C] Table salt
[D] All are ionic solids
Show Answer
Correct Answer: C [Table salt]
Notes:
One important character of Ionic solids is that they readily get dissolved in water
7. Carbon monoxide poisoning is the most common type of fatal air poisoning in many parts of the world. What makes it such a fatal gas?
[A] CO dissolves in cytoplasm and functions as an inhibitor of the crucial enzymes for metabolism
[B] CO competes with Haemoglobin for Oxygen intake
[C] CO dissolves in blood Plasma and spreads toxicity
[D] CO converts into Carbon Dioxide in presence of water in Blood
Show Answer
Correct Answer: B [ CO competes with Haemoglobin for Oxygen intake]
Notes:
Carbon monoxide is colourless, odourless, and tasteless, but highly toxic because it combines with haemoglobin to produce carboxyhemoglobin, which usurps the space in haemoglobin that normally carries oxygen, but is ineffective for delivering oxygen to bodily tissues. Concentrations as low as 667 ppm may cause up to 50% of the body’s hemoglobin to convert to carboxyhemoglobin. The impact is irreversible and that is why that even after available of oxygen, the carboxyhemoglobin does not allow the Oxygen to be taken up.
8. The vegetable oil treated with which among the following halogens makes it an additive, which is used in artificial citrus flavoured aerated drinks to give it the cloudy look, so that consumers get deceived because it appears natural citrus drink?
[A] Chlorine
[B] Bromine
[C] Iodine
[D] Fluorine
Show Answer
Correct Answer: B [ Bromine]
Notes:
Brominated Vegetable Oil is an additive, which is used in artificial citrus flavoured aerated drinks to give it the cloudy look, so that consumers are fooled into believing that it is the real thing. India banned BVO in 1988. It is used in some countries.
9. Which of the following laws is used as a rule to predict the solubility of gases in metals?
[A] Dalton’s Law
[B] Sievert’s law
[C] Graham’s law
[D] Henry’s law
Show Answer
Correct Answer: B [ Sievert’s law]
Notes:
Sievert’s law is used as a rule in physical metallurgy to predict the solubility of gases in metals.
10. What is the chemical name of Quick lime?
[A] Calcium peroxide
[B] Calcium oxide
[C] Calcium dioxide
[D] Calcium hydroxide
Show Answer
Correct Answer: B [Calcium oxide]
Notes:
The chemical name of Quick Lime is Calcium Oxide (CaO).
