Chemistry MCQs

Notes:
LPG is composed hydrocarbons containing three or four carbon atoms. The normal components of LPG thus, are propane (C₃H₈), butane (C₄H₁₀) and Methane (CH₄). Small concentrations of other hydrocarbons may also be present.

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.”

Notes:
Noble metals, such as gold, silver, and platinum, are primarily characterized by their non-reactive nature. This means they resist oxidation and corrosion, making them ideal for use in jewelry and electronics. Unlike base metals, noble metals do not easily form compounds with other elements, which is why they maintain their luster and appearance over time. Their rarity and preciousness are secondary characteristics, but their chemical stability is what truly defines them as noble.

Notes:
The correct answer is Helium. Helium is a non-flammable, lighter-than-air gas, making it safe for use in balloons. Unlike hydrogen, which is highly flammable and poses explosion risks, helium is inert and does not react with other substances. Helium is the second most abundant element in the universe, primarily produced through nuclear fusion in stars. It was first discovered in the sun before being found on Earth.

Notes:
The main constituent of vegetable oil and animal fats is triglyceride. Triglycerides are composed of three fatty acids linked to a glycerol molecule. They are the most common type of fat found in the body and serve as a major energy source. In fact, triglycerides account for about 95% of the fats in the human diet.

Notes:
Chile saltpetre, or sodium nitrate (NaNO3), differs from regular saltpetre, which typically refers to potassium nitrate (KNO3). Chile saltpetre is primarily composed of sodium, while traditional saltpetre contains potassium. Historically, Chile saltpetre was extensively mined in the Atacama Desert and was crucial for fertilizer and explosives in the 19th century.

Notes:
The correct set of copper ores in the same order of Sulfide deposits, Carbonate deposits, and Silicate deposits is:

[A] Chalcopyrite, Azurite, Dioptase

So, option [A] is the correct answer.

Notes:
Buna-S is a synthetic rubber formed by co-polymerization of a mixture of 1:3 butadiene and styrene. It is obtained from Sodium.

Notes:
Ground Level Ozone results from photochemical reactions between oxides of nitrogen (NO_x) and volatile organic compounds (VOCs) in the presence of sunlight.

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.