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 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. Haber Process is used to produce which among the following?
[A] Potash
[B] Ammonia
[C] Urea
[D] Nitrates
Show Answer
Correct Answer: B [Ammonia]
Notes:
The Haber Process is an industrial method for synthesizing ammonia from nitrogen and hydrogen gases. Developed by Fritz Haber and Carl Bosch in the early 20th century, it operates under high pressure and temperature, using an iron catalyst. Ammonia produced is crucial for fertilizers, supporting global agriculture. The process importantly increased food production, earning Haber the Nobel Prize in Chemistry in 1918.
4. Which among the following minerals is also known as Horn Silver?
[A] Silver Iodide
[B] Silver Chroride
[C] Zinc Phosphate
[D] Silver Sulphide
Show Answer
Correct Answer: B [Silver Chroride]
Notes:
Chlorargyrite is the mineral form of silver chloride (AgCl). It is also known as cerargyrite and, when weathered by desert air, as horn silver. Silver chloride is formed by the disappearance of the initial silver oxide layer.
5. Which of the following element is NOT an alkaline earth metal?
[A] Magnesium
[B] Strontium
[C] Barium
[D] Beryllium
Show Answer
Correct Answer: D [Beryllium]
Notes:
The elements of Group 2 include beryllium, magnesium, calcium, strontium, barium and radium. These elements with the exception of beryllium are commonly known as the alkaline earth metals.
6. Which of the following represents the general formula for alkanes?
[A] CnH2n
[B] CnH2n-2
[C] CnH2n+2
[D] CnHn
Show Answer
Correct Answer: C [CnH2n+2]
Notes:
Alkanes are saturated open chain hydrocarbons containing carbon – carbon single bonds.
7. How is Aqua regia formed?
[A] by mixing 2 parts of concentrated HCl and one part of concentrated HNO3
[B] by mixing 3 parts of concentrated HCl and one part of concentrated HNO3
[C] by mixing 1 part of concentrated HCl and three parts of concentrated HNO3
[D] None of the above
Show Answer
Correct Answer: B [by mixing 3 parts of concentrated HCl and one part of concentrated HNO3]
Notes:
When three parts of concentrated HCl and one part of concentrated HNO3 are mixed, aqua regia is formed which is used for dissolving noble metals, e.g., gold, platinum.
8. Which of the following Metal-Ore pairs is not correct?
[A] Iron – Magnetite
[B] Aluminium – Bauxite
[C] Gold – Calaverite
[D] Calcium – Carnalite
Show Answer
Correct Answer: D [Calcium – Carnalite]
Notes:
Carnalite is an ore of Potassium. It’s a hydrated potassium magnesium chloride. The chemical formula of Carnalite is KCl. MgCl2 . 6H2O.
9. Which of the following refining methods works on the principle of adsorbtion?
[A] Zone refining
[B] Vapour Phase refining
[C] Chromatographic methods
[D] Liquation
Show Answer
Correct Answer: C [Chromatographic methods]
Notes:
Chromatographic methods are based on the principle that different components of a mixture are differently adsorbed on an adsorbent. There are several chromatographic techniques used for refining such as paper chromatography, column chromatography, gas chromatography, etc
10. What is the S.I unit of activity?
[A] becquerel
[B] curie
[C] candela
[D] henry
Show Answer
Correct Answer: A [becquerel]
Notes:
The SI unit for activity is becquerel, named after the discoverer of radioactivity, Henry Becquerel. The c.g.s unit of activity is curie.
