Chemistry MCQs

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Nitrous oxide (NO), commonly known as laughing gas or happy gas, is the most commonly used inhalation anesthetic in dentistry and is commonly used in emergency centers and ambulatory surgery centers as well. It is an inorganic inhalation agent that is colorless, odorless to sweet-smelling, and non-irritating to the tissues.

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Sodium hypochlorite bleaches are also called chlorine or liquid household bleach. They are the more powerful laundry bleaches. They are used to whiten and disinfect laundry, typically either 5.25 percent (regular strength) or 6 percent sodium hypochlorite (ultra strength).

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Soap solution is used to measure the hardness of rain water, temporarily hard water and sea-water. Hard water does not form lather with soap. This is because magnesium ions or calcium ions present in hard water react with soap to form calcium stearate or magnesium stearate forming water insoluble scum.

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Borax (Na2B4O7.10H2O) is also known as Sodium borate or Sodium Tetraborate Decahydrate. It is an important boron compound, a mineral, and a salt of boric acid. Borax is a component of many detergents, cosmetics, and enamel glazes and is also used to make buffer solutions in biochemistry, as a fire retardant, as an anti-fungal compound, etc.

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An organic compound must contain at least carbon. Most chemists agree hydrogen must also be present. Depending upon the arrangement of carbon atoms in their structure, organic compounds are broadly categorized into Acyclic or Open Chain compounds and Cyclic or Closed Chain compounds.

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Uranium, Thorium and Polonium are radioactive elements which do not have stable naturally occurring isotope. Aluminium is a silvery white, soft, ductile metal with stable nucleus in its atoms. It is the third most abundant element (after oxygen and silicon), and the most abundant metal in the Earth’s crust.

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Chloroform can be used as Anaesthetic. Chloroform (CHCl3) on heating with silver powder undergoes dehalogenation to form Ethyne. It is also an important source for producing foxic phosgene gas.

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In Dumas’ method, a known quantity of nitrogen containing organic compound is heated strongly with excess of copper oxide in an atmosphere of carbon dioxide to produce free nitrogen in addition to carbon dioxide and water.

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Baeyer’s reagent is an alkaline solution of potassium permanganate, which is a powerful oxidant. It is used in organic chemistry in a qualitative test for finding the presence of unsaturation. i.e. presence or absence of double or triple bond in hydrocarbon.

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Carbon is one of the elements which shows allotropy. Allotropic of carbon can be either amorphous or crystalline. Three most famous ‘allotropes’ of pure carbon are diamond, graphite and Buckminster fullerene (C-60). In all three allotropes, the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.