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. In what form is Nitrogen present in Urea?
[A] Nitrite
[B] Nitrate
[C] Ammonium
[D] Amide
Show Answer
Correct Answer: D [Amide]
Notes:
Urea is an organic compound with the formula (NH2)2CO. The Nitrogen present in Urea is in the form of Amide. This compound is highly soluble in water and is a very effective source of Nitrogen for plants. It is the main nitrogenous end product of the metabolic breakdown of proteins in all mammals and some fishes.
3. The easily noticed smell of the LPG gas is because of which among the following?
[A] Butane
[B] Propane
[C] Methane
[D] Ethanethiol
Show Answer
Correct Answer: D [Ethanethiol]
Notes:
Ethanethiol or stench, is a organosulfur compound and is used to add to the otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks.
4. Cassiterite is a primary ore of which of the following elements?
[A] Iron
[B] Zinc
[C] Copper
[D] Tin
Show Answer
Correct Answer: D [Tin]
Notes:
Cassiterite is a mineral that is a significant ore of tin. It is also known as tin oxide. Although rare, its key characteristic is its high specific gravity that makes it easy to separate it from other materials. Tin, which is extracted from Cassiterite, is commonly used in making alloys, punches, and cutting tools.
5. Which among the following basic atoms are must in an Alkaloid?
[A] Sodium
[B] Nitrogen
[C] Magnesium
[D] Potassium
Show Answer
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. 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
7. Which among the following gas has lowest auto-ignition temperature?
[A] Methane
[B] Hydrogen
[C] Ethylene
[D] Carbon Di Sulphide
Show Answer
Correct Answer: D [Carbon Di Sulphide]
Notes:
The auto-ignition temperature of a liquid, gas or vapor is the temperature at which the substance will ignite without any external heat source. Here is the temperature of some gases:
Methane -580 °C
Hydrogen -560 °C
Propane -493 °C
Ethylene -425 °C
Acetylene -305 °C
Naphtha -290 °C
Carbon disulfide -102 °C
8. 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.
9. Which of these ores is not an oxide?
[A] Sphalerite
[B] Haematite
[C] Cuprite
[D] Magnetite
Show Answer
Correct Answer: A [Sphalerite]
Notes:
Sphalerite (ZnS) is a sulphide. All others are oxides. Haematite and Magnetite are the oxides of iron and Cuprite is an oxide of Copper.
10. Which of the following is also known as Alumina?
[A] AlO2
[B] Al2O3
[C] Al2O4
[D] Al2CO2
Show Answer
Correct Answer: B [Al2O3]
Notes:
Alumina is the common name given to aluminum oxide (Al2O3). It is produced from bauxite to get pure aluminium metal.
