Chemistry MCQs

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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.

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Plaster of Paris is calcium sulphate hemihydrate. The formula is given as, CaSO4.1/2 H2O or (2 CaSO4) . H2O. The powder is called plaster of Paris, because the gypsum which was used to get the powder was mainly found in Paris.

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Helium, a noble gas, is the second most abundant element in the universe after Hydrogen. It is colorless, odorless, tasteless, non-toxic, and non-reactive because its outermost electron shell is full with two electrons. This complete outer shell gives it the stability that defines the Noble Gases. Despite its abundance in the universe, Helium is relatively rare on Earth, primarily obtained from natural gas wells.

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Phenolphthalein is commonly employed as a pH indicator in titrations due to its distinct color change in varying pH levels. At pH 8.2, it appears colorless but turns pink as the pH increases to 10. It is not used as a solvent, catalyst or detergent. It also finds applications in forensic science for detecting latent blood stains.

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Ilmenite is a titanium-iron oxide mineral with the formula FeTiO3. India holds about 37% of global ilmenite reserves, primarily along the peninsular coastal regions. Ilmenite is the primary source of titanium, used in aerospace, chemical, and medical industries. The Geological Survey of India ranks ilmenite among the most abundant heavy minerals in Indian beach placers. Titanium extraction from ilmenite is commercially viable.

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The funda is that when a small drop of a strong acid, such as nitric acid, is put onto the metal’s surface, most metals fizz or bubble, whilst precious metals (Gold or Platinum not silver) are unaffected.

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The compounds with identical molecular formula but different structures are called structural isomers.

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Centrifugation is a mechanical process that utilizes an applied centrifugal force field to separate the components of a mixture.

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Carnalite is an ore of Potassium. It’s a hydrated potassium magnesium chloride. The chemical formula of Carnalite is KCl. MgCl₂ . 6H₂O.

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Chromatographic methods are based on the principle that different components of a mixture are differently adsorbed on an adsorbent. There are several chromatographic techniques used for refining such as paper chromatography, column chromatography, gas chromatography, etc