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. Carnotite is a mineral of which among the following metals?
[A] Lead
[B] Uranium
[C] Aluminium
[D] Iron
Show Answer
Correct Answer: B [Uranium]
Notes:
Carnotite is an ore of Uranium and comprises potassium, vanadium, water and few other elements such as calcium, barium, magnesium, iron, sodium etc. It is a yellow colored mineral.
3. 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.
4. If a baby diaper is subjected to different solutions, which of the following will it absorb the maximum quantity of?
[A] Distilled Water
[B] Drinking Water
[C] Hard Water
[D] Urine
Show Answer
Correct Answer: A [Distilled Water]
Notes:
A baby diaper can absorb the maximum quantity of distilled water as it lacks impurities such as minerals and ions that are present in other type of water. The absorbent materials in diapers, often polymers called sodium polyacrylate, can hold up to 30 times their weight in distilled water, making them highly efficient.
5. Sodium bicarbonate decomposes above 70 °C, making it usable in bakery products. What end product of this thermal decomposition process contributes to its use in baking?
[A] Hydrogen
[B] Carbon Dioxide
[C] Water Vapor
[D] Sodium Carbonate
Show Answer
Correct Answer: B [Carbon Dioxide]
Notes:
Sodium bicarbonate, commonly known as baking soda, is used in baking due to its ability to decompose above 70 degrees Celsius and release carbon dioxide. This chemical reaction is given by the equation 2 NaHCO3 – Na2CO3 + H2O + CO2. In baking, it reacts with other ingredients or decomposes at high temperatures to produce carbon dioxide, which causes the dough to rise, creating the fluffy texture in baked goods.
6. 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.
7. Which of the following chemicals is resposible for temporary acid rain in colder regions?
[A] Hydrogen chloride
[B] Sulphur dioxide
[C] Nitric acid
[D] Nitrogen oxides
Show Answer
Correct Answer: A [ Hydrogen chloride]
Notes:
Hydrogen chloride gas released from volcanic eruption is responsible for temporary acid rain in colder regions.
8. Which of the following is the softest metal?
[A] Cesium
[B] Lead
[C] Gold
[D] Silver
Show Answer
Correct Answer: A [ Cesium]
Notes:
Cesium is extremely reactive metal. It reacts with water even at −116 °C (−177 °F). It is the least electronegative element. Cesium is also the softest known metal. It is so soft that it can be cut with a butter knife.
9. Which of the following is NOT correct about Alkynes?
[A] They contain at least two triple bond between two carbon atoms
[B] The number of hydrogen atoms is less in alkynes as compared to alkenes
[C] The general formula of Alkynes is CnH2n–2
[D] All are correct
Show Answer
Correct Answer: A [They contain at least two triple bond between two carbon atoms]
Notes:
Alkynes contain at least one triple bond between two carbon atoms. The number of hydrogen atoms is less in alkynes as compared to alkenes or alkanes. Their general formula is CnH2n–2.
10. What is dry ice?
[A] solidified form of Carbon dioxide
[B] frozen heavy water
[C] isotope of Hydrogen
[D] popular name of Benzene
Show Answer
Correct Answer: A [solidified form of Carbon dioxide]
Notes:
Carbon dioxide can be obtained as a solid in the form of dry ice by allowing the liquified CO2 to expand rapidly.
