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 an alkaline earth metal?
[A] Pottasium
[B] Lead
[C] Copper
[D] Calcium
Show Answer
Correct Answer: D [Calcium ]
Notes:
The six elements in column 2 of the Periodic table are called Alkaline Earth Metals. These include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
2. How many noble gases occur naturally?
[A] Three
[B] Four
[C] Five
[D] Six
Show Answer
Correct Answer: D [Six]
Notes:
Noble gases are characterized by their low reactivity. The reason for this is their full electron shell, which makes them very stable and unlikely to engage in chemical reactions. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). Despite the inertness of noble gases, some of them like Xenon are known to form compounds.
3. Ground Level Ozone is formed due to reaction between:
[A] VOCs, Oxides of Nitrogen & Sunlight
[B] VOCs, Sulphur dioxide & Sunlight
[C] Ozone, Sulphur dioxide & Oxides of Nitrogen
[D] Ozone, Oxides of Nitrogen & Sunlight
Show Answer
Correct Answer: A [VOCs, Oxides of Nitrogen & Sunlight]
Notes:
Ground Level Ozone results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
4. Which of the following is not an isotope of Hydrogen?
[A] Protium
[B] Para hydrogen
[C] Deuterium
[D] Tritium
Show Answer
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.
5. Which of the following chemicals is also known as "Vitriol of clay”?
[A] Aluminium sulphate
[B] Sodium silicate
[C] Zinc sulphate
[D] Copper(II) sulphate
Show Answer
Correct Answer: A [ Aluminium sulphate]
Notes:
Aluminium sulphate is also known as Vitriol of clay. It is soluble in water and is mainly used as a flocculating agent in the purification of drinking water
6. How many electrons can the s-orbital accommodate?
[A] 1
[B] 2
[C] 8
[D] 16
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.
7. Which of the following is the composition of vinegar?
[A] 65-75% solution of acetic acid in water
[B] 45-60% solution of acetic acid in water
[C] 28-35% solution of acetic acid in water
[D] 5-8% solution of acetic acid in water
Show Answer
Correct Answer: D [5-8% solution of acetic acid in water]
Notes:
5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles
8. 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.
9. Which of the following is emitted in Beta-decay process?
[A] Electron
[B] Positron
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
In beta decay, a nucleus spontaneously emits an electron (βdecay) or a positron (β+decay). One can never predict which nucleus will undergo decay.
10. Which of the following factors affect the rate of chemical reaction?
[A] Concentration of reactants
[B] Temperature
[C] Catalyst
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The rate of reaction depends upon the experimental conditions such as concentration of reactants (pressure in case of gases), temperature and catalyst.
