Chemistry MCQs

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Fluorine is most active because it has the highest electronegativity.

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Rayon is the first man-made fiber, also known as “artificial silk”. It was developed in the late 19th century as a substitute for natural silk. Rayon is a semi-synthetic fiber made from wood pulp. It has properties similar to silk and a shiny appearance.  Nylon is the first fully synthetic fiber. It is made from coal, water, and air. Nylon is strong, elastic, and easy to wash. It is used to make socks, ropes, tents, and more.

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Sodium benzoate is commonly used as a preservative in food and beverages, including tomato juice. It inhibits the growth of mold, yeast, and some bacteria, extending shelf life. It is effective in acidic environments, such as those found in tomato products, where the pH is typically below 4.6. Sodium chloride (salt) can also act as a preservative but is primarily used for flavor. Sodium carbonate and sodium lauryl sulfate are not suitable preservatives for tomato juice.

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Iodine-135 is a important by-product of nuclear fission, particularly in reactors using uranium fuel. It has a high neutron capture cross-section, meaning it effectively absorbs neutrons, which can inhibit the fission process and reduce reactor power output. This property makes it crucial for managing reactor control and safety, as its presence can lead to a phenomenon known as “neutron poison,” affecting the overall efficiency of the nuclear reaction.

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The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases.

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The scattering of a beam of light by the particles of a colloid is called the Tyndall effect.

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In alpha decay, Helium nucleus is emitted. Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus transforms or ‘decays’ into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

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Rusting is the corrosion of Iron in which iron (Fe) combines with oxygen to form rust, or iron oxide. Fe₂O₃. nH₂O is usually called as hydrated ferric Oxide.

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The 3d transition series starts from scandium (Z = 21) and completes at zinc (Z=30). Reason for this transition series is that before the 4p orbital is filled, filling up of 3d orbitals becomes energetically favourable.

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If conductivity(κ) of the solution is expressed in S m² and the concentration(c) is expressed in mol m^-3, then the units of Molar conductivity are expressed in S m² mol^-1.