Chemistry MCQs

Notes:
Non-metallic minerals are those minerals which do not contain metals. Examples of Non-Metallic minerals include limestone, mica, coal, gypsum, dolomite, phosphate, salt, granite etc.

Notes:
Rayon is the first man-made fiber, also known as “artificial silk”. It was developed in the late 19th century as a substitute for natural silk. Rayon is a semi-synthetic fiber made from wood pulp. It has properties similar to silk and a shiny appearance.  Nylon is the first fully synthetic fiber. It is made from coal, water, and air. Nylon is strong, elastic, and easy to wash. It is used to make socks, ropes, tents, and more.

Notes:
Oxalic acid is an organic compound with the formula C₂H₂O₄. Some call it “crab acid” due to its appearance. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid.

Notes:
Nitrolim is a type of fertilizer that was widely used in the past. The main components of Nitrolim are calcium carbide and nitrogen. Calcium carbide reacts with nitrogen to form calcium cyanamide, which is an active ingredient in Nitrolim. This fertilizer is significant as it helps in fixing nitrogen in the soil thereby promoting plant growth.

Notes:
Water at 4 degrees Celsius has maximum density. This is due to the unique molecular structure of water, which allows it to reach its highest density at this temperature. As water cools from higher temperatures, it becomes denser until it reaches 4 degrees. below this temperature, it begins to expand, making ice less dense than liquid water. This phenomenon is crucial for aquatic life, as it allows ice to float, insulating the water below.

Notes:
Helium atoms that have lost two electrons are called alpha rays. Alpha rays are also called alpha particles or alpha radiation. Alpha particles are made up of two protons and two neutrons bound together into a particle that is identical to a helium-4 nucleus.
Alpha particles are named after the first letter in the Greek alphabet, α. They were the first nuclear radiation to be discovered.
When a helium atom loses its electrons, it is left with only the nucleus. This is called an alpha particle.

Notes:
The electric heating is also used to produce light, as in an electric bulb. Here, the filament must retain as much of the heat generated as is possible, so that it gets very hot and emits light. It must not melt at such high temperature. A strong metal with high melting point such as tungsten (melting point 3380°C) is used for making bulb filaments. The filament should be thermally isolated as much as possible, using insulating support, etc. The bulbs are usually filled with chemically inactive nitrogen and argon gases to prolong the life of filament. Most of the power consumed by the filament appears as heat, but a small part of it is in the form of light radiated.

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 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:
The correct answer is Chlorine. – Gammaxene (also known as Lindane) is a pesticide derived from hexachlorocyclohexane, which involves chlorine. – D.D.T. (Dichloro-Diphenyl-Trichloroethane) is a synthetic pesticide containing chlorine. – Bleaching powder (calcium hypochlorite) is a chlorine compound used for disinfection and bleaching. Chlorine is essential in various chemical processes and compounds, particularly in agriculture and sanitation.