Chemistry MCQs

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Methanol (CH₃OH) is also known as Wood Alcohol. It’s a solvent in many chemical processes and is a component of automobile antifreeze.

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Oxidation is the loss of electrons during a reaction by a molecule, atom or ion. When oxidation occurs, an element loses electrons and its oxidation number increases .i.e. it becomes more positive.

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Crookes glass comprises Cerium oxide (CiO2) which sharply absorbs the ultraviolet rays from the sunlight. It is used in making lenses of eye glasses.

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Calamine is an ore that contains zinc carbonate along with impurities like iron oxide. Through smelting, the zinc carbonate in calamine can be reduced to extract pure zinc metal. Other common zinc ores are sphalerite (zinc sulfide) and smithsonite (zinc carbonate). So calamine is considered a zinc ore due to its zinc carbonate content.

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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.

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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.

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One of the most important chemical components of the troposphere is the ‘hydroxyl radical’: a highly reactive substance composed of an oxygen and a hydrogen atom, denoted ‘OH’. Hydroxyl radicals react with just about any other trace gas they encounter, removing them from the atmosphere.For example, OH combines with toxic carbon monoxide to generate carbon dioxide. In this sense, OH ‘cleans up’ the troposphere, and is sometimes called the detergent of the atmosphere.

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In India, the Double Sulphitation is the most commonly used method for refining of sugar. Also, it is the cheapest process of refining sugar as compared to other available process.

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Plaster of Paris is the common name of calcium sulphate hemihydrate because half molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO₄.1/2H₂O.

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Suspension is a heterogeneous mixture. The particles of a suspension can be seen by the naked eye. The solute particles can be separated from the mixture by the process of filtration.