Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. What is the key element used in the batteries of electric vehicles?
[A] Magnesium
[B] Lithium
[C] Sodium
[D] Bromine
Show Answer
Correct Answer: B [Lithium]
Notes:
The primary component for electric vehicle batteries is Lithium, used as Lithium carbonate or Lithium hydroxide. These Lithium-ion batteries have a high power-to-weight ratio, energy efficiency, and thermal stability, leading to their prevalence in electric vehicles. Notably, the boom in EVs has significantly driven the demand for Lithium globally.
2. Which among the following is the correct set of chemical formulae of Chile Saltpetre, Saltpetre and Quick Lime?
[A] KNO3, NaNO3, CaO
[B] NaNO3, KNO3, Ca(OH)2
[C] Na(OH)2, KOH, CaO
[D] NaNO3, KNO3, CaO
Show Answer
Correct Answer: D [NaNO3, KNO3, CaO]
Notes:
Saltpetre, also spelled Saltpeter, also called Nitre, or Niter, any of three naturally occurring nitrates, distinguished as (1) ordinary saltpetre, or potassium nitrate, KNO3; (2) Chile saltpetre, cubic nitre, or sodium nitrate, NaNO3; and (3) lime saltpetre, wall saltpetre, or calcium nitrate, Ca(NO3)2.
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound.
3. Which among the following is the most abundant organic compound in nature?
[A] Glucose
[B] Fructose
[C] Sucrose
[D] Cellulose
Show Answer
Correct Answer: D [Cellulose]
Notes:
Cellulose is the most abundant organic compound in nature. It is the main constituent of plant fiber. Plants contain on average 33% cellulose, and cotton is the purest form at 90%. Chitin is the second most abundant organic compound in nature.
4. What is commonly referred to as “Laughing Gas”?
[A] Nitric oxide
[B] Nitrous oxide
[C] Nitrogen penta oxide
[D] Nitrogen
Show Answer
Correct Answer: B [Nitrous oxide]
Notes:
Nitrous oxide is often referred to as “Laughing Gas” due to the euphoric effect it produces when inhaled. Its chemical formula is N2O and it is an oxide of nitrogen. At room temperature, it is a colorless, non-flammable gas with a relatively sweet odor and taste. It is primarily used in dentistry and surgery for its analgesic and anesthetic properties. It is also noted for its role as a major greenhouse gas and air pollutant, as well as a natural regulator of stratospheric ozone.
5. Cassiterite is most important source of which of these metals?
[A] Nickel
[B] Tin
[C] Tungsten
[D] Silver
Show Answer
Correct Answer: B [Tin ]
Notes:
Cassiterite is a mineral that is primarily composed of tin dioxide (SnO2). It is the most important source of tin, and is also used as a semi-precious gemstone. Cassiterite is typically found in igneous and metamorphic rocks, and is often associated with other minerals such as quartz, feldspar, and mica. It has a high melting point and is resistant to weathering, making it a useful material for many industrial applications. The name “cassiterite” comes from the Greek word “kassiteros,” which means “tin.”
6. Mizoroki-Heck reaction is catalyzed by which of the following metals?
[A] Rhodium
[B] Sodium
[C] Palladium
[D] Osmium
Show Answer
Correct Answer: C [Palladium]
Notes:
The Mizoroki-Heck reaction is a cross-coupling reaction that typically involves the coupling of aryl halides with alkenes. It is primarily catalyzed by palladium (Pd) complexes. Palladium is favored due to its ability to facilitate the oxidative addition and reductive elimination steps essential for the reaction. Rhodium, while also a transition metal, is less commonly used for this specific reaction. The Mizoroki-Heck reaction is important in organic synthesis for forming carbon-carbon bonds and is widely utilized in pharmaceuticals and materials science.
7. Pyrolusite, Braunite, Psilomelane, Rhodochrosite are the ores of which among the following metals?
[A] Manganese
[B] Aluminium
[C] Copper
[D] Manganese and Copper
Show Answer
Correct Answer: A [Manganese]
Notes:
Pyrolusite, Braunite, Psilomelane, and Rhodochrosite are all ores of Manganese. Pyrolusite is one of the most important ores due to its high manganese content. Braunite, although a significant ore, its manganese content is less than Pyrolusite. Psilomelane and Rhodochrosite also contribute as minor ores.
8. What is the chemical name of Quick lime?
[A] Calcium peroxide
[B] Calcium oxide
[C] Calcium dioxide
[D] Calcium hydroxide
Show Answer
Correct Answer: B [Calcium oxide]
Notes:
The chemical name of Quick Lime is Calcium Oxide (CaO).
9. 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.
10. Which of the following is the correct order of the decreasing order of abundance of the elements in earth’s crust?
[A] Iron > Silicon > Oxygen >Aluminium
[B] Oxygen > Silicon > Aluminium > Iron
[C] Oxygen> Iron > Aluminium > Silicon
[D] Iron > Aluminium > Silicon > Oxygen
Show Answer
Correct Answer: B [Oxygen > Silicon > Aluminium > Iron]
Notes:
Oxygen is the most abundant element in the earth’s crust followed by Silicon, Aluminium and Iron. It comprises almost half of the mass of the earth’s crust.