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 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.
2. Water at 4 degree centigrade has____?
[A] minimum density
[B] maximum density
[C] No density
[D] None of the above
Show Answer
Correct Answer: B [maximum density]
Notes:
Water at 4 degrees Celsius has maximum density. This is due to the unique molecular structure of water, which allows it to reach its highest density at this temperature. As water cools from higher temperatures, it becomes denser until it reaches 4 degrees. below this temperature, it begins to expand, making ice less dense than liquid water. This phenomenon is crucial for aquatic life, as it allows ice to float, insulating the water below.
3. Which among the following suspension in water is often called milk of magnesia because of its milk-like appearance?
[A] Magnesium Carbonate
[B] Magnesium Hydroxide
[C] Magnesium Lactate
[D] Magnesium Oxide
Show Answer
Correct Answer: B [Magnesium Hydroxide]
Notes:
Magnesium Hydroxide in water is often called milk of magnesia because of its milk-like appearance. Magnesium hydroxide is the inorganic compound and occurs in nature as the mineral brucite.
4. Which of the following is NOT correct about Ethanol?
[A] It is a good solvent
[B] It gives out hydrogen when reacted with Sodium
[C] It is an odorless liquid
[D] All are correct
Show Answer
Correct Answer: C [It is an odorless liquid]
Notes:
Ethanol is a good solvent and reacts with sodium leading to the evolution of hydrogen. It is a colorless liquid with a slight characteristic odor.
5. Which of the following is correct about the properties of a solution?
[A] The particles of a solution can be seen by naked eyes
[B] The particles of a solution scatter a beam of light passing through the solution
[C] The solute particles do not settle down when left undisturbed
[D] All of the above
Show Answer
Correct Answer: C [The solute particles do not settle down when left undisturbed]
Notes:
The particles of a solution are smaller than 1 nm in diameter. So, they cannot be seen by naked eyes. Because of very small particle size, they do not scatter a beam of light passing through the solution. The solute particles do not settle down when left undisturbed, that is, a solution is stable.
6. What do we call the process that separates a pure solid in the form of its crystals from a solution?
[A] Crystallisation
[B] Sublimation
[C] Chromatography
[D] Distillation
Show Answer
Correct Answer: A [Crystallisation]
Notes:
Crystallisation is a process that separates a pure solid in the form of its crystals from a solution. For example: purification of the salt obtained from sea water.
7. Which of the following is an endothermic reaction?
[A] Decomposition of calcium carbonate to calcium oxide and carbon dioxide
[B] Respiration
[C] Burning of Natural gas
[D] All of the above
Show Answer
Correct Answer: A [Decomposition of calcium carbonate to calcium oxide and carbon dioxide]
Notes:
Decomposition of calcium carbonate to calcium oxide and carbon dioxide is an endothermic reaction. Respiration and Burning of Natural gas are examples of exothermic reactions.
8. Which of the following comprises a standard hydrogen electrode?
[A] a copper electrode coated with carbon black
[B] an iron electrode coated with platinum black
[C] a platinum electrode coated with platinum black
[D] a gold electrode coated with carbon black
Show Answer
Correct Answer: C [a platinum electrode coated with platinum black]
Notes:
The standard hydrogen electrode consists of a platinum electrode coated with platinum black. According to convention, a half-cell called standard hydrogen electrode is assigned a zero potential at all temperatures corresponding to the reaction.
9. What is the product when Methane reacts with steam in the presence of Nickel catalyst?
[A] Carbon dioxide and ethane
[B] Ethyne
[C] Carbon monoxide and dihydrogen
[D] Carbon monoxide and Water vapour
Show Answer
Correct Answer: C [Carbon monoxide and dihydrogen]
Notes:
Methane reacts with steam at 1he temperature of 273 K in the presence of nickel catalyst to form carbon monoxide and dihydrogen. This method is used for industrial preparation of dihydrogen gas.
10. Which of the following is a cross linked polymer?
[A] Bakelite
[B] Melamine
[C] Formaldehyde resin
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
These are polymers in which long polymer chains are crosslinked together to from a three dimensional network. bakelite, melamine and formaldehyde resin are some examples of this type.
