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 is the objective of the Methyl tert-butyl ether (MTBE) mixing with Petroleum?
[A] Raise Octane Number
[B] Antioxidant Stabilizer
[C] Lead Scavanger
[D] Fuel Dye
Show Answer
Correct Answer: A [Raise Octane Number ]
Notes:
MTBE is a gasoline additive, used as an oxygenate to raise the octane number. Its use is controversial in the US and declining in that country in part because of its occurrence in groundwater and legislation favoring ethanol.
2. Which among the following substances is most suitable for making Compact Discs?
[A] PVC
[B] Polyethylene
[C] Polyamides
[D] Polycarbonates
Show Answer
Correct Answer: D [Polycarbonates
]
Notes:
Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.
3. Which among the following is known as White Vitriol?
[A] Zinc Sulphate
[B] Zinc Chloride
[C] Zinc Phosphate
[D] Zinc oxide
Show Answer
Correct Answer: A [Zinc Sulphate]
Notes:
Zinc sulfate is the inorganic compound with the formula ZnSO4 and historically known as “white vitriol” Zinc sulfate is an inorganic compound and dietary supplement.
4. Which among following is also known as white gold?
[A] Nickel
[B] Rhodium
[C] Platinum
[D] Palladium
Show Answer
Correct Answer: C [Platinum]
Notes:
Platinum is a naturally white metal. It doses not need to be alloyed for color. Due to its appearance as white, it is commonly known as White Gold.
5. Which among the following of a catalyst does not change at the end of a reaction?
[A] Quantity
[B] Chemical Composition
[C] Both Quantity and Chemical com position
[D] None of the above
Show Answer
Correct Answer: C [Both Quantity and Chemical com position]
Notes:
A catalyst is a substance that increases the rate of a chemical reaction without undergoing any permanent change itself. At the end of the reaction, a catalyst retains its original quantity and chemical composition. This property allows it to be used repeatedly in reactions. For example, enzymes, which are biological catalysts, remain unchanged after facilitating biochemical reactions.
6. Which among the following allotropes of Oxygen is found in 6 phases under various pressures and temperatures?
[A] Ozone
[B] Tetra oxygen
[C] Octaoxygen
[D] None of them
Show Answer
Correct Answer: C [Octaoxygen]
Notes:
The correct answer is Octaoxygen. Octaoxygen (O8) is an allotrope of oxygen that can exist in multiple phases under varying pressures and temperatures. It was first synthesized in 2001 and is notable for its unique molecular structure, which consists of eight oxygen atoms. Ozone (O3) is well-known but does not exhibit multiple phases like octaoxygen. Tetraoxygen (O4) is less stable and not commonly referenced in the same context.
7. Which of the following are two predominant acids of acid rain?
[A] sulphuric acid and nitric acid
[B] carbonic acid and hydrochloric acid
[C] nitric acid and hydrochloric Acid
[D] hydrofluoric acid and hydrochloric Acid
Show Answer
Correct Answer: A [ sulphuric acid and nitric acid ]
Notes:
Acid rain, or acid deposition, is a broad term that includes any form of precipitation with acidic components, such as sulphuric or nitric acid that fall to the ground from the atmosphere in wet or dry forms.
8. What is the hemihydrate of calcium sulphate commonly known as?
[A] Gypsum
[B] Plaster of Paris
[C] Chloroform
[D] Limestone
Show Answer
Correct Answer: B [Plaster of Paris]
Notes:
Plaster of Paris is the common name of calcium sulphate hemihydrate because half molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO4.1/2H2O.
9. Bell metal is an alloy of which of the following metals?
[A] Copper and Tin
[B] Copper and Mercury
[C] Copper and Lead
[D] Copper and Zinc
Show Answer
Correct Answer: A [Copper and Tin]
Notes:
Bell metal is a form of bronze with a higher tin content. It is an alloy of copper and tin (typically, 78% copper, 22% tin by mass). It is used for making bells and related instruments, such as cymbals.
10. Which method will is most suitable to separate the mixture of ammonium chloride and salt?
[A] Evaporation
[B] Sublimation
[C] Simple Distillation
[D] All of the above
Show Answer
Correct Answer: B [Sublimation]
Notes:
Sublimation is the property of substance in which they are converted directly from solid to gas or vice versa. Ammonium chloride is a sublime solid.
