Chemistry MCQs

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Group 11 is also known as the coinage metals, due to their former usage. They were most likely the first three elements discovered. Copper, silver, and gold all occur naturally in elemental form.

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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.

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Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.

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Potassium permanganate is a point-of-entry treatment method that oxidizes dissolved iron, manganese, and hydrogen sulfide into solid particles that are filtered out of the water. It can also be used to control iron bacteria growth in wells.

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Cellulose is the most abundant organic compound in nature. It is the main constituent of plant fiber. Plants contain on average 33% cellulose, and cotton is the purest form at 90%. Chitin is the second most abundant organic compound in nature.

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Nitrous oxide is often referred to as “Laughing Gas” due to the euphoric effect it produces when inhaled. Its chemical formula is N2O and it is an oxide of nitrogen. At room temperature, it is a colorless, non-flammable gas with a relatively sweet odor and taste. It is primarily used in dentistry and surgery for its analgesic and anesthetic properties. It is also noted for its role as a major greenhouse gas and air pollutant, as well as a natural regulator of stratospheric ozone.

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Graphite is renowned for its conspicuous uses owing to its unique properties like its ability to conduct electricity, which makes it ideal for electrode manufacturing. It’s also used as a lubricant and in the production of crucibles, thanks to its high melting point. However, it isn’t used in glass cutting.

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The first synthetic plastic was actually celluloid, invented by Alexander Parkes in 1855. Initially, celluloid was primarily used in photographic films. However, it had limitations, not suitable for making containers or electrical insulation. The first genuine plastic, Bakelite, was invented by Leo Baekeland in 1909 and extensively used in various applications, including safely handled autos. World War I significantly contributed to the development of polystyrene and polyvinyl chloride, widely used in plumbing and electrical insulation. Later, in the 1930s, nylon was invented, and by 1950, plastic materials gained immense popularity.

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Third option is the correct answer
Photochemical smog is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone.

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Bell metal is a form of bronze with a higher tin content. It is an alloy of copper and tin (typically, 78% copper, 22% tin by mass). It is used for making bells and related instruments, such as cymbals.