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 the poorest conductor of heat in comparison to other options?
[A] Silver
[B] Copper
[C] Lead
[D] Mercury
Show Answer
Correct Answer: C [ Lead ]
Notes:
Silver is best conductor of heat while among metals lead is poorest conductor of heat. Cooper and aluminum are good conductor while mercury is a poor conductor.
2. Which of the following is a thermosetting plastic?
[A] Polythene
[B] Bakelite
[C] Polyvinyl chloride
[D] Casseine
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Correct Answer: B [Bakelite]
Notes:
Bakelite is a thermosetting plastic formed from phenol and formaldehyde, used in electrical insulators and cookware handles. Unlike thermoplastics, it hardens irreversibly when heated and cannot be remolded. It was the first synthetic plastic, invented by Leo Baekeland in 1907.
3. Which of the following is not a common use of Graphite?
[A] Manufacturing of electrodes
[B] As a lubricant
[C] Manufacturing of crucibles
[D] In glass cutting
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Correct Answer: D [In glass cutting]
Notes:
Graphite is renowned for its conspicuous uses owing to its unique properties like its ability to conduct electricity, which makes it ideal for electrode manufacturing. It’s also used as a lubricant and in the production of crucibles, thanks to its high melting point. However, it isn’t used in glass cutting.
4. Which among the following groups is characteristic to alcohols?
[A] OH group
[B] COOH group
[C] COO group
[D] CO group
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Correct Answer: A [OH group]
Notes:
Alcohols are organic compounds characterized by the presence of a hydroxyl group, denoted as -OH. This group consists of one oxygen atom bonded to a hydrogen atom. Due to the presence of the hydroxyl group, alcohols exhibit unique properties, such as the ability to form hydrogen bonds, making them polar. Alcohols are distinct from carboxylic acids (COOH), carbonates (COO), and carbonyl group compounds (CO).
5. Which among the following basic atoms are must in an Alkaloid?
[A] Sodium
[B] Nitrogen
[C] Magnesium
[D] Potassium
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Correct Answer: B [Nitrogen]
Notes:
Alkaloids are a class of naturally occurring organic compounds that mostly contain basic nitrogen atoms. Nitrogen is essential in their structure, contributing to their pharmacological properties. Common examples of alkaloids include morphine, caffeine, and nicotine, all of which contain nitrogen. Sodium, magnesium, and potassium are not fundamental components of alkaloids.
6. 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.
7. In which of the following cases, components can be separated using a separating funnel?
[A] Mixture of acetone and water
[B] Mixture of oil and water
[C] Different gases in the air
[D] None of the above
Show Answer
Correct Answer: B [Mixture of oil and water]
Notes:
A separating funnel can be used to separate the components of the mixture of immiscible liquids. Components in the mixture of oil and water can be separated using this method.
8. Which of the following alpha-emitter is commonly used in smoke detectors?
[A] Bismuth – 209
[B] Amrecium-231
[C] Uranium-238
[D] Protactinium-231
Show Answer
Correct Answer: B [Amrecium-231]
Notes:
Americium-241 is an isotope of americium. It is the most common isotope of americium having a half-life of 432.2 years. It is radioactive and is commonly used in ionization type smoke detectors.
9. 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
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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.
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.
