Chemistry MCQs

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Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, soluble in carbon disulfide and composed of highly condensed polycyclic aromatic hydrocarbons.

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Sodium sulfate, used as a filler in detergent powder, enables the adjustment of the concentration of the active matter in the detergent, as required.

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Carbamide is another name of Urea, an organic compound with chemical formula CO(NH₂)₂. This name indicates that Urea is an amide in which two –NH₂ groups are joined by a carbonyl (C=O) functional group.

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Normal rainfall is slightly acidic due to the presence of carbonic acid, which forms when carbon dioxide (CO2) dissolves in water. The pH of normal rainwater is typically around 5.6, making it mildly acidic. This natural acidity is a result of the CO2 in the atmosphere, which is produced by respiration, combustion, and other natural processes.

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An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer. The emission of a gamma ray from an excited nuclear state allows the nucleus to lose energy and reach either a lower energy state, sometimes its ground state. In certain cases, the excited nuclear state following a nuclear reaction or other type of radioactive decay, has a half live that is more than 100 to 1000 times longer than the average 10-12 seconds, and this excited state is referred to as a metastable nuclear excited state. Some nuclei are able to stay in this metastable excited state for minutes, hours, days, or occasionally far longer, before undergoing gamma decay, in which they undergo radioactive decay with primary emission of a gamma ray.

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Ionization energy is the quantity of energy required to remove loosely bound electron from an atom.

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The ionization enthalpies of the alkali metals are considerably low and decrease down the group from Li to Cs.

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Ammonia is a colourless gas with a pungent odour. Its aqueous solution is weakly basic due to the formation of OH^– ions. The ammonia molecule is trigonal pyramidal in shape.

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Calcination is the process of converting an ore into its oxide by heating it in a limited supply of air or in absence of air, below its melting point. It is used to convert the concentrated ore to its oxide.

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Galena is an ore of Lead. It is also known as lead glance. It is the natural mineral form of lead sulfide (PbS).