Chemistry MCQs

Notes:
Chlorargyrite is the mineral form of silver chloride (AgCl). It is also known as cerargyrite and, when weathered by desert air, as horn silver. Silver chloride is formed by the disappearance of the initial silver oxide layer.

Notes:
Sublimation is a transition from solid to gas, bypassing the liquid phase. Iodine sublimes, producing violet vapors; naphthalene sublimes, hence its use in mothballs; and camphor also sublimes, used in medicinal and aromatic applications. Thus, all three substances exhibit sublimation upon heating, making ‘All of them’ the correct answer.

Notes:
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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Hydrogen chloride gas released from volcanic eruption is responsible for temporary acid rain in colder regions.

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Lithium ions has maximum degree of hydration and for this reason lithium salts are mostly hydrated.

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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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Sodium carbonate is commonly known as Washing soda. Sodium Hydrogencarbonate is commonly known as Caustic soda. Ethanoic acid is commonly known as Acetic acid. calcium oxychloride is commonly known Bleaching powder.

Notes:
Field’s metal is an alloy of bismuth, indium, and tin, with the following percentages by weight: 32.5% Bi, 51% In, 16.5% Sn. Dutch metal, Prince’s metal and Muntz metal are a form of brass.

Notes:
Magnetite > Haemetite > Limonite > Siderite . Magnetite has 72.4% iron content. Haematite has 70% iron content. Limonite has 55% iron content. Siderite has 48.2% iron content.

Notes:
van Arkel method is used for refining Titanium: This method is very useful for removing all the oxygen and nitrogen present in the form of impurity in Titanium.