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. Which among the following is the objective of the Methyl tert-butyl ether (MTBE) mixing with Petroleum?
[A] Raise Octane Number
[B] Antioxidant Stabilizer
[C] Lead Scavanger
[D] Fuel Dye
Show Answer
Correct Answer: A [Raise Octane Number ]
Notes:
MTBE is a gasoline additive, used as an oxygenate to raise the octane number. Its use is controversial in the US and declining in that country in part because of its occurrence in groundwater and legislation favoring ethanol.
3. The chemical oxygen demand COD test is commonly used to measure which of the following?
[A] amount of organic compounds in water
[B] amount of oxygen in water
[C] amount of oxygen in a chemical
[D] amount of oxygen used in a oxygenation process
Show Answer
Correct Answer: A [amount of organic compounds in water]
Notes:
chemical oxygen demand is a measure of water quality and is amount of organic pollutants found in surface water. Potassium permanganate has been used for many years to measure COD
4. L.P.G. is a hydrocarbon consisting of a mixture of :
[A] Methane and Butane
[B] Propane and Butane
[C] Ethane and Propane
[D] Ethane and Butane
Show Answer
Correct Answer: B [Propane and Butane]
Notes:
L.P.G. (Liquefied Petroleum Gas) primarily consists of propane and butane. It is used as fuel for heating, cooking, and vehicles. Propane (C3H8) and butane (C4H10) are both byproducts of natural gas processing and petroleum refining. LPG is favored for its high energy content and clean-burning properties.
5. Which of the following is not a metalloid?
[A] Boron
[B] Silicon
[C] Germanium
[D] Titanium
Show Answer
Correct Answer: D [ Titanium]
Notes:
The most commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. The other less recognised metalloids are: carbon, aluminium, selenium, polonium and astatine.Titanium is a lustrous transition metal with a silver color, low density and high strength.
6. Which of the following laws states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture?
[A] Raoult’s law
[B] Henry’s law
[C] Graham’s law
[D] Sievert’s law
Show Answer
Correct Answer: A [ Raoult’s law]
Notes:
Raoult’s law states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture.
7. Which of the following is correct about the atomic and ionic radii of the alkaline earth metals?
[A] it is smaller than corresponding alkali metals in the same periods
[B] it is larger than corresponding alkali metals in the same periods
[C] It is same as the corresponding alkali metals in the same periods
[D] None of the above
Show Answer
Correct Answer: A [it is smaller than corresponding alkali metals in the same periods]
Notes:
The atomic and ionic radii of the alkaline earth metals are smaller than corresponding alkali metals in the same periods due to the increased nuclear charge in these elements.
8. Which of the following elements have a compound named as Hydrogen peroxide?
[A] Hydrogen, Carbon and Oxygen
[B] Hydrogen only
[C] Hydrogen and Oxygen
[D] Hydrogen, Oxygen and Potassium
Show Answer
Correct Answer: C [Hydrogen and Oxygen]
Notes:
Hydrogen peroxide is a compound of Hydrogen and Oxygen.
9. What is the hemihydrate of calcium sulphate commonly known as?
[A] Gypsum
[B] Plaster of Paris
[C] Chloroform
[D] Limestone
Show Answer
Correct Answer: B [Plaster of Paris]
Notes:
Plaster of Paris is the common name of calcium sulphate hemihydrate because half molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO4.1/2H2O.
10. Which of the following metals is extracted and refined in the Mond’s process?
[A] Cobalt
[B] Bismuth
[C] Nickel
[D] Copper
Show Answer
Correct Answer: C [Nickel]
Notes:
The Mond process is a technique to extract and purify nickel. It is also known as the carbonyl process. In this, nickel is heated in a stream of carbon monoxide forming a volatile complex, nickel tetracarbonyl.
