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 not a correct statement about Bitumen?
[A] It’s a mixture of highly condensed polycyclic aromatic compounds
[B] Its is soluble in Carbon Disulphide
[C] SARA analysis is used to determine bitumen chemistry
[D] All of above are correct statements
Show Answer
Correct Answer: D [ All of above are correct statements ]
Notes:
Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, soluble in carbon disulfide and composed of highly condensed polycyclic aromatic hydrocarbons.
2. Haber Process is used to produce which among the following?
[A] Potash
[B] Ammonia
[C] Urea
[D] Nitrates
Show Answer
Correct Answer: B [Ammonia]
Notes:
The Haber Process is an industrial method for synthesizing ammonia from nitrogen and hydrogen gases. Developed by Fritz Haber and Carl Bosch in the early 20th century, it operates under high pressure and temperature, using an iron catalyst. Ammonia produced is crucial for fertilizers, supporting global agriculture. The process importantly increased food production, earning Haber the Nobel Prize in Chemistry in 1918.
3. In the E-waste generated by the Mobile Phones, which among the following metal is most abundant?
[A] Copper
[B] Silver
[C] Palladium
[D] Gold
Show Answer
Correct Answer: A [Copper]
Notes:
The sources of e-waste are faulty desktop computers, cables, printers, refrigerators, air conditioners, televisions, electronic and electrical devices. E-waste generated by the Mobile Phones are copper, silver, gold, palladium. Among them copper is found abundantly.
4. In a photochemical smog, which gas causes irritation to mucous membrane and respiratory system?
[A] Nitrous oxide
[B] Sulphur dioxide
[C] Ozone
[D] Carbon monoxide
Show Answer
Correct Answer: C [ Ozone]
Notes:Ozone (O3) is the most common photochemical oxidant in photochemical smog. Inhaling ozone can cause irritation to the mucous membrane and respiratory system. Ozone can also cause chest constriction and damage to vegetation.
Other components of photochemical smog include:
- Nitrogen dioxide (NO2)
- Peroxyacetylnitrate (PAN)
- Aldehydes
Other air pollutants that can be harmful to humans include:
- Sulfur dioxide
- Volatile organic compounds (VOCs)
- Dioxins
- Polycyclic aromatic hydrocarbons (PAHs)
Carbon monoxide can cause hyperventilation, respiratory distress, and stillbirths. At high levels, carbon monoxide can even cause direct poisoning.
5. Brass is an alloy of which of the following metals?
[A] Copper and Tin
[B] Copper and Zinc
[C] Lead and Tin
[D] Zinc and Nickel
Show Answer
Correct Answer: B [Copper and Zinc]
Notes:
Brass is an alloy of copper and zinc (Cu and Zn). Lead is often added in concentrations of around 2% to enhance the machinability of brass.
6. What is Rose metal?
[A] It is an alloy of Nickel, Tin and Zinc
[B] It is an alloy of Bismuth, Copper and Palladium
[C] It is an alloy of Palladium, Tin and Lead
[D] It is an alloy of Bismuth, Tin and Lead
Show Answer
Correct Answer: D [It is an alloy of Bismuth, Tin and Lead]
Notes:
Rose metal is an alloy of Bismuth, Tin and Lead. It’s a fusible alloy with low melting point commonly used for soldering.
7. Which of the following statements is correct about Beta-decay?
[A] In β+decay, Mass number increases by 2
[B] In β−decay, Mass number decreases by 2
[C] In β−decay, the atomic number increases by 1
[D] None of the above
Show Answer
Correct Answer: C [In β−decay, the atomic number increases by 1]
Notes:
In both β− and β+ decay, the mass number A remains unchanged. In β− decay, the atomic number of the nucleus goes up by 1, while in β+ decay, the atomic number goes down by 1.
8. Which of the following represents the reaction of Calcium oxide and water to form Slaked lime?
[A] Displacement reaction
[B] Combination reaction
[C] Double Displacement reaction
[D] None
Show Answer
Correct Answer: B [Combination reaction]
Notes:
A reaction in which a single product is formed from two or more reactants is known as a combination reaction. For example: calcium oxide and water combine to form a single product, slaked lime or calcium hydroxide.
9. Which of the following gas is used to prevent the chips from getting oxidised?
[A] Oxygen
[B] Nitrogen
[C] Helium
[D] Lithium
Show Answer
Correct Answer: B [Nitrogen]
Notes:
The chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidised.
10. What is the order of the reaction which is independent of the concentration of reactants?
[A] Zero order
[B] First order
[C] Second order
[D] Third order
Show Answer
Correct Answer: A [Zero order]
Notes:
Order of a reaction can be 0, 1, 2, 3 and even a fraction. A zero order reaction means that the rate of reaction is independent of the concentration of reactants.
