Chemistry MCQs

Notes:
The carat is the common unit used to describe the mass of a gem. A 1-carat diamond, for example, has a mass of 0.20 g. The karat is the common unit used to describe the purity of a precious metal, such as gold. A 24-karat gold ring is as pure as can be. A gold ring that is 50 % pure is 12 karat.

Notes:
Acetic acid (CH3COOH) is a weak organic acid that gives vinegar its sour taste. At household concentrations (5-8% acetic acid), it is a mild acid. Vinegar can be made from a variety of base ingredients including wine, apple cider, rice, or malt. The acetic acid is produced by fermentation of the sugars in these ingredients. The most common type of vinegar in households is white distilled vinegar which is typically 4-7% acetic acid. It has a strong, pungent smell and flavor.

Notes:
A cotton wick soaked in pure honey, when lit with a matchstick, will burn consistently. This is primarily due to the high sugar content of the honey acting as fuel for the flame. Contrary to common misconceptions, honey doesn’t produce much smoke or any unusual sounds during combustion.

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MTBE is a gasoline additive, used as an oxygenate to raise the octane number. Its use is controversial in the US and declining in that country in part because of its occurrence in groundwater and legislation favoring ethanol.

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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.

Notes:
Adsorption, the binding of gas or liquid particles to a solid surface, is often used in chromatography – a laboratory technique for the separation of a mixture. This process is critical as it allows the separation of the compounds in the mixture, thereby enabling further analysis or purification. Apart from chromatography, adsorption is also used in scrubbers and purification of solids and liquids.

Notes:
Kazimierz Funk (1884 – 1967) was a Polish biochemist, and one of the first to formulate the concept of Vitamins.

Notes:
The correct answer is Aryl. In organic chemistry, when a hydrogen atom is removed from a benzene ring (a hydrocarbon), the remaining structure is referred to as an aryl group. Aryl groups are derived from aromatic compounds, specifically those containing a benzene ring. For example, when a hydrogen is removed from toluene (methylbenzene), the resulting aryl group is called a tolyl group. Aryl groups are important in various chemical reactions and are foundational in the synthesis of many organic compounds.

Notes:
A baby diaper can absorb the maximum quantity of distilled water as it lacks impurities such as minerals and ions that are present in other type of water. The absorbent materials in diapers, often polymers called sodium polyacrylate, can hold up to 30 times their weight in distilled water, making them highly efficient.

Notes:
The sources of e-waste are faulty desktop computers, cables, printers, refrigerators, air conditioners, televisions, electronic and electrical devices. E-waste generated by the Mobile Phones are copper, silver, gold, palladium. Among them copper is found abundantly.