Chemistry MCQs

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Caffeine (1, 3, 7-trimethylxanthine) also known as ancient wonder drug is a basically a neurostimulant easily available all over the world and is used in different products like tea, coffee, analgesic adjuvant, soft drinks and many dietary supplements.

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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.

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Noble gases are characterized by their low reactivity. The reason for this is their full electron shell, which makes them very stable and unlikely to engage in chemical reactions. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). Despite the inertness of noble gases, some of them like Xenon are known to form compounds.

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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

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The correct answer is Oxidation. This reaction occurs when minerals in rocks, particularly iron-bearing minerals, react with oxygen. This process can lead to the formation of iron oxides, which give rocks a reddish or yellowish hue. For example, rusting of iron in rocks is a common oxidation reaction. Oxidation is a important weathering process, contributing to soil formation and landscape changes.

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The correct answer is Mercury. An amalgam is a specific type of alloy that primarily consists of mercury mixed with another metal, commonly used in dental fillings due to its durability and ease of use. Historically, amalgams have been used since ancient times, with the earliest known use dating back to the 9th century in China.

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Typical composition of the Coal gas is as follows: •Hydrogen 50% •Methane 35% •Carbon monoxide 10% •Ethylene 5%

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The chemical name of Quick Lime is Calcium Oxide (CaO).

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Francium is highly radioactive. its longest-lived isotope ²²³Fr has a half-life of only 21 minutes.

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Crystallisation is a process that separates a pure solid in the form of its crystals from a solution. For example: purification of the salt obtained from sea water.