Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. 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.
2. What happens to the weight of Iron, when it rusts?
[A] Increases for long time
[B] Decreases then increases
[C] Increases then decreases
[D] Remains the same
Show Answer
Correct Answer: C [Increases then decreases]
Notes:
When iron or any other metal oxidizes, oxygen from the air combines with the iron to make iron oxide or rust. So, weight of the bar increases, due to the increased weight of oxygen which has combined with the iron. over time, the weight of the iron bar will tend to decrease, due to factors related more to erosion than to chemistry.
3. What is the electrical state of a molecule, considered the smallest part of matter retaining the properties of the original matter?
[A] Positive
[B] Negative
[C] Either positive or negative
[D] Neutral
Show Answer
Correct Answer: D [Neutral]
Notes:
A molecule represents the smallest portion of a substance that retains the characteristics of the substance. It’s electrically neutral because it’s made up of atoms that bond together, sharing or exchanging electrons to achieve stability. This process balances out the electrical charges of the protons and electrons, rendering the molecule as a whole electrically neutral.
4. Duralumin which is used in making aero planes is an alloy consisting of _____?
[A] Aluminum & Copper
[B] Aluminum, Copper & Manganese
[C] Aluminum, Copper, Manganese & Magnesium
[D] Aluminum and zinc
Show Answer
Correct Answer: C [Aluminum, Copper, Manganese & Magnesium]
Notes:
Duralumin is an alloy primarily composed of aluminum, copper, manganese, and magnesium. It was developed in the early 20th century and is known for its high strength-to-weight ratio, making it ideal for aircraft construction. The addition of copper enhances strength, while manganese and magnesium improve corrosion resistance and workability. Duralumin was first used in aircraft during World War I, revolutionizing aviation materials.
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 is correct regarding the alkaline battery ?
[A] Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & electrolyte is KOH
[B] Negative terminal made of Manganese dioxide and Positive terminal made of Zinc powder & electrolyte KOH
[C] Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & Electrolyte is Ammonium Chloride
[D] Negative terminal made of Manganese dioxide and Positive terminal made of Zinc powder & electrolyte Ammonium Chloride
Show Answer
Correct Answer: A [Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & electrolyte is KOH]
Notes:
The correct statement is that in an alkaline battery, the negative terminal is made of zinc powder, the positive terminal is made of manganese dioxide, and the electrolyte is potassium hydroxide (KOH). Alkaline batteries are known for their long shelf life and higher energy density compared to zinc-carbon batteries. They were invented in the 1950s and are widely used in household devices.
7. After a nuclear disaster, the Strontium-90 becomes an health issue of great concern. What is the major concern about this particular isotope?
[A] Strontium-90 gets deposited in the Red Blood Cells and causes Blood Cancer
[B] Strontium-90 gets deposited in the Liver cells and causes Liver Cirrhosis
[C] Strontium-90 gets deposited in bones and bone marrow and causes cancer
[D] None of the above is a correct statement
Show Answer
Correct Answer: C [ Strontium-90 gets deposited in bones and bone marrow and causes cancer]
Notes:
Strontium-90 is a “bone seeker” that exhibits biochemical behaviour similar to calcium, the next lighter Group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70–80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marrow, with the remaining 1% remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukaemia.
8. Which of the following is correct about suspension?
[A] It is a heterogeneous mixture
[B] The particles of a suspension can be seen by naked eyes
[C] The particles can be separated from the mixture by the process of filtration
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Suspension is a heterogeneous mixture. The particles of a suspension can be seen by the naked eye. The solute particles can be separated from the mixture by the process of filtration.
9. Which of the following is correct about Solder?
[A] It is an alloy of lead and tin
[B] It is used for welding electrical wires together
[C] It has a low melting point
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Solder is an alloy of lead and tin (Pb and Sn). It has a low melting point and is used for welding electrical wires together.
10. Which of the following is a correct statement about minerals and ores?
[A] All minerals are ores
[B] All ores are minerals
[C] Minerals are the native form in which various metals exist
[D] Ores are usually used to extract metals economically
Show Answer
Correct Answer: A [All minerals are ores]
Notes:
All ores are minerals but all minerals are not ores. Minerals are the native form in which various metals exist and ores are those minerals which are used to extract metals economically.
