Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Out of the following options, which group of elements is typically found in a free state?
[A] Group 11 elements
[B] Group 12 elements
[C] Group 13 elements
[D] Group 14 elements
Show Answer
Correct Answer: A [Group 11 elements]
Notes:
Group 11 elements, which include copper, silver, and gold, have been known since ancient times. These elements are found in the Earth’s crust in a free or native state, due to their low reactivity compared to other elements. This is why these elements were used by ancient civilizations for crafting tools, jewelry, and early forms of money.
2. Which among the following kinds of glass is used generally in making of the Bullet proof screens?
[A] Pyrex glass
[B] Jena glass
[C] Reinforced Glass
[D] Flint Glass
Show Answer
Correct Answer: C [Reinforced Glass]
Notes:
Reinforced Glass or Toughened glass or tempered glass is a kind of safety glass is used as s a component of bulletproof glass, for diving masks, and various types of plates and cookware.
3. Which among the following is Quick Silver?
[A] Aluminium
[B] Mercury
[C] Lead
[D] Zinc
Show Answer
Correct Answer: B [Mercury]
Notes:
Mercury is a chemical element with the symbol Hg and atomic number 80. The element is also known as quicksilver for its mobility. Mercury is one of the oldest and deadliest poisons, a highly toxic metal mined from a brilliant red ore.
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 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.
6. What is Carbamide?
[A] A Pesticide
[B] A Fertilizer
[C] A Textile Dye
[D] An Explosive
Show Answer
Correct Answer: B [A Fertilizer]
Notes:
Carbamide is another name of Urea, an organic compound with chemical formula CO(NH2)2. This name indicates that Urea is an amide in which two –NH2 groups are joined by a carbonyl (C=O) functional group.
7. Choose the incorrect ‘Alloy – constituent metal’ pair:
[A] Lockalloy – Iron
[B] Vitallium – Cobalt
[C] Italma – Aluminium
[D] Constantan – Copper
Show Answer
Correct Answer: A [Lockalloy – Iron]
Notes:
Lockalloy is an alloy that contains 62% beryllium and 38% aluminum. All other pairs are correctly matched.
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. What do we call the ratio of number of fission produced by a given generation of neutrons to the number of fission of the preceding generation?
[A] Critical factor
[B] Energy factor
[C] Multiplication factor
[D] Moderation factor
Show Answer
Correct Answer: C [Multiplication factor]
Notes:
The multiplication factor is the ratio of number of fission produced by a given generation of neutrons to the number of fission of the preceding generation.
10. What happens to the effective nuclear charge as we move from left to right in the periodic table?
[A] It increases
[B] it decreases
[C] It remains constant
[D] It increases till 4th group then decreases
Show Answer
Correct Answer: A [It increases]
Notes:
The effective nuclear charge of an element increases as we move from left to right in the periodic table.
