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. The Alkali metals are called good reducing agents. This implies that__:
[A] They easily capture electrons
[B] They are not stable at room temperature
[C] They easily lose electrons
[D] They don’t act with dilute acids
Show Answer
Correct Answer: C [They easily lose electrons ]
Notes:
Alkali metals have one electron in their valence shell and hence they easily lose or donate electron.
3. Galvanizing is a metallurgical process that is used to coat steel or iron with which of the following?
[A] Zinc
[B] Lead
[C] Chromium
[D] Copper
Show Answer
Correct Answer: A [Zinc]
Notes:
Galvanisation is a method of protecting steel and iron from rusting by coating them with a thin layer of zinc
4. Steel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by weight. An increasing amount of Iron will result in which of the following?
[A] Increase Hardening
[B] Decrease Hardening
[C] Increase ductility
[D] Increase melting Point
Show Answer
Correct Answer: A [Increase Hardening]
Notes:
Increasing the amount of iron in steel generally leads to increased hardening. This is due to the formation of a solid solution where carbon atoms occupy interstitial spaces in the iron lattice, enhancing strength and hardness. Steel’s carbon content is crucial. higher carbon levels (up to 2.1%) improve hardness but reduce ductility. The melting point of steel is also influenced by its composition, but the primary effect of increasing iron is hardening.
5. 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.
6. Which of the following is the use of washing soda?
[A] softening of water
[B] manufacture of glass
[C] manufacture of paints
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
It is used for softening of water, laundering, cleaning, manufacture of glass, soap, borax, paper, paints and textile It is also extensively used as laboratory reagent.
7. Which of the following is correct about the properties of a solution?
[A] The particles of a solution can be seen by naked eyes
[B] The particles of a solution scatter a beam of light passing through the solution
[C] The solute particles do not settle down when left undisturbed
[D] All of the above
Show Answer
Correct Answer: C [The solute particles do not settle down when left undisturbed]
Notes:
The particles of a solution are smaller than 1 nm in diameter. So, they cannot be seen by naked eyes. Because of very small particle size, they do not scatter a beam of light passing through the solution. The solute particles do not settle down when left undisturbed, that is, a solution is stable.
8. Hydraulic Washing:
- is used for concentration of ores
- is based on differences in magnetic properties of the ore components
Which of the above is / are correct?
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: A [Only 1 ]
Notes:
Hydraulic Washing is a method used for concentration of ores. It is a type of gravity separation as it is based on the differences in gravities of the ore and the gangue particles.
9. Which of the following is also known as Alumina?
[A] AlO2
[B] Al2O3
[C] Al2O4
[D] Al2CO2
Show Answer
Correct Answer: B [Al2O3]
Notes:
Alumina is the common name given to aluminum oxide (Al2O3). It is produced from bauxite to get pure aluminium metal.
10. What is the probability of finding an electron at a point within an atom?
[A] proportional to the square of the orbital wave function
[B] proportional to the orbital wave function
[C] proportional to the twice of the orbital wave function
[D] proportional to the cube of the orbital wave function
Show Answer
Correct Answer: A [proportional to the square of the orbital wave function]
Notes:
The probability of finding an electron at a point within an atom is proportional to the square of the orbital wave function i.e., ψ|2 at that point. |ψ|2 is known as probability density and is always positive.
