Chemistry MCQs

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A high-refractive-index polymer is a polymer that has a refractive index greater than 1.50. Such materials are required for anti-reflective coating and photonic devices such as light emitting diodes (LEDs) and image sensors.

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The agricultural industry widely uses urea, a white crystalline solid containing 46 percent nitrogen as an animal feed additive and fertilizer. Urea has the highest nitrogen content of all solid fertilizers at 46% N.

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Oxidation is the loss of electrons during a reaction by a molecule, atom or ion. When oxidation occurs, an element loses electrons and its oxidation number increases .i.e. it becomes more positive.

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In the human body the most common bio-elements (in decreasing order of occurrence) are oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Other bio-elements include sodium, potassium, magnesium, and copper.

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LPG is composed hydrocarbons containing three or four carbon atoms. The normal components of LPG thus, are propane (C₃H₈), butane (C₄H₁₀) and Methane (CH₄). Small concentrations of other hydrocarbons may also be present.

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A molecule represents the smallest portion of a substance that retains the characteristics of the substance. It’s electrically neutral because it’s made up of atoms that bond together, sharing or exchanging electrons to achieve stability. This process balances out the electrical charges of the protons and electrons, rendering the molecule as a whole electrically neutral.

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If water is heated ,it vapor pressure will increase. Latent heat is the reason for high temperature and pressure of vapour.

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Pewter is primarily composed of tin, typically around 85-95%, with the remainder often consisting of copper, antimony, or bismuth. Historically, pewter was used for making utensils and decorative items due to its malleability and low melting point. The use of tin in pewter dates back to ancient civilizations, including the Romans and Egyptians, who valued it for its corrosion resistance and ease of casting.

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The correct answer is Technetium. It has the atomic number 43 and is the lowest atomic number element without any stable isotopes. All of its isotopes are radioactive, with Technetium-98 being the most stable, having a half-life of about 4.2 million years. Technetium was first artificially produced in 1937 by Carlo Perrier and Emilio Segrè, making it the first element to be artificially created.

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Diethyl ether is a colourless, highly volatile & flammable organic compound. It was earlier used for anaesthesia but after the development of non-flammable drugs, its uses as anaesthetic has been reduced.