Chemistry MCQs

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Saltpetre, also spelled Saltpeter, also called Nitre, or Niter, any of three naturally occurring nitrates, distinguished as (1) ordinary saltpetre, or potassium nitrate, KNO3; (2) Chile saltpetre, cubic nitre, or sodium nitrate, NaNO3; and (3) lime saltpetre, wall saltpetre, or calcium nitrate, Ca(NO3)2.
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound.

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Hydrogen (H2) gas is utilized in the manufacture of Vanaspati ghee from vegetable oils. The process involves hydrogenation, a chemical reaction between molecular hydrogen (H2) and another compound or element. Hydrogenation of vegetable oils helps to convert them into a semisolid form that resembles ghee, often used as a cheaper alternative to butter or ghee in cooking.

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Cobalt Oxide is commonly used to create a distinctive blue hue in glasses and ceramics. The depth of the blue can be altered by changing the concentration of the oxide. In addition to being used for aesthetic purposes, Cobalt blue, which results from Cobalt Oxide, is also used because it absorbs certain wavelengths of light, making it useful for filtering out unwanted wavelengths.

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Duralumin is an alloy primarily composed of aluminum, copper, manganese, and magnesium. It was developed in the early 20th century and is known for its high strength-to-weight ratio, making it ideal for aircraft construction. The addition of copper enhances strength, while manganese and magnesium improve corrosion resistance and workability. Duralumin was first used in aircraft during World War I, revolutionizing aviation materials.

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The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated carbon compounds.

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Amalgam is the general name given to an alloy of mercury with some other metal. It can be a solid, liquid or a soft paste depending on the composition of the constituents.

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The number of protons present in the nucleus of an atom or the number of electrons in a neutral atom is equal to its atomic number. It is represented by Z.

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Q-value is the net kinetic energy gained in the process or, if the initial nucleus X is at rest, the kinetic energy of the products. Clearly, Q> 0 for exothermic processes such as α-decay.

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The emission of electron in β⁻decay is accompanied by the emission of an antineutrino (ν ) and in β⁺ decay, a neutrino (ν) is generated.

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In both β⁻ and β⁺ decay, the mass number A remains unchanged. In β⁻ decay, the atomic number of the nucleus goes up by 1, while in β⁺ decay, the atomic number goes down by 1.