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 among the following are constituents of Brass?
[A] Zinc and Copper
[B] Iron and Zinc
[C] Copper and Nickel
[D] Iron and Copper
Show Answer
Correct Answer: A [Zinc and Copper ]
Notes:
Brass is an alloy of Copper and Zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. The proportions of Zinc and Copper can vary to create different types of brass alloys with varying mechanical and electrical properties.
2. A cotton wick dipped in pure honey when ignited with a matchstick will ______?
[A] Burn steadily
[B] Burn with a cracking sound
[C] Not burn at all
[D] Burn producing a large amount of smoke
Show Answer
Correct Answer: A [Burn steadily]
Notes:
A cotton wick soaked in pure honey, when lit with a matchstick, will burn consistently. This is primarily due to the high sugar content of the honey acting as fuel for the flame. Contrary to common misconceptions, honey doesn’t produce much smoke or any unusual sounds during combustion.
3. PVC is a polymer of__?
[A] Propane
[B] Vinyl chloride
[C] Styrene
[D] Carbonates
Show Answer
Correct Answer: B [Vinyl chloride]
Notes:
Polyvinyl chloride (PVC) is made from the monomer vinyl chloride (CH2 =CHCl). It is used for making raincoats, handbags, toys including dolls, electrical goods and as a covering of electrical wires.
4. Which of the following chemicals is also known as “Chinese snow”?
[A] Silver iodide
[B] Potassium nitrate
[C] Ammonium chloride
[D] Sodium phosphate
Show Answer
Correct Answer: B [ Potassium nitrate]
Notes:
Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpetre or saltpetre. It is also known as “Chinese snow”. Major uses of potassium nitrate are in fertilizers, rocket propellants and fireworks.
5. Which of the following alkali metal ions has the highest hydration enthalpy?
[A] Lithium
[B] Sodium
[C] Potassium
[D] Caesium
Show Answer
Correct Answer: A [Lithium]
Notes:
Lithium ions has maximum degree of hydration and for this reason lithium salts are mostly hydrated.
6. Galena is an ore of which of the following metals?
[A] Tin
[B] Copper
[C] Lead
[D] Gold
Show Answer
Correct Answer: C [Lead]
Notes:
Galena is an ore of Lead. It is also known as lead glance. It is the natural mineral form of lead sulfide (PbS).
7. What can be the maximum number of electrons in a shell, if principal quantum number is n?
[A] n
[B] n2
[C] 2n2
[D] 3n3
Show Answer
Correct Answer: C [2n2]
Notes:
The general formula is that the nth shell can hold up to 2n2 electrons. For example: for L shell n =2, so maximum number of electrons will be 2(22) i.e. 8.
8. What is the relationship between becquerel and curie unit?
[A] 1 curie = 0.5 Bq
[B] 1 curie = 9 × 106 Bq
[C] 1 curie = 3.7 × 1010 Bq
[D] 1 curie = 5.7 Bq
Show Answer
Correct Answer: C [1 curie = 3.7 × 1010 Bq]
Notes:
1 curie = 1 Ci = 3.7 × 1010 decays per second = 3.7 × 1010 Bq. This is approximately the amount of radioactivity emitted by one gram (1 g) of radium-226. The ‘curie’ unit is named after Pierre Curie, a French physicist.
9. How many periods and groups are there in the Modern Periodic table?
[A] 18 groups, 7 periods
[B] 16 groups, 18 periods
[C] 7 groups, 18 periods
[D] 14 groups, 8 periods
Show Answer
Correct Answer: A [18 groups, 7 periods]
Notes:
The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’.
10. What is the shape of SF4 molecule?
[A] Bent
[B] See-saw
[C] Trigonol Pyramidal
[D] T-shape
Show Answer
Correct Answer: B [See-saw]
Notes:
SF4 molecule is see-saw in shape. It has 4-bonding pairs of electrons and one lone pair of electrons.
