Chemistry MCQs

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Photochromatic or Photochromic glass acquires a darker shade when exposed to bright light and returns to its original lighter shade in dim light. This happens because silver halides (iodide or chloride)  is added to this glass

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Alkali metals have one electron in their valence shell and hence they easily lose or donate electron.

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Gobar Gas or Biogas is mostly methane (CH₄) and carbon dioxide (CO₂) and may have small amounts of hydrogen sulfide (H₂S), moisture and siloxanes.

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Nitrolim is a type of fertilizer that was widely used in the past. The main components of Nitrolim are calcium carbide and nitrogen. Calcium carbide reacts with nitrogen to form calcium cyanamide, which is an active ingredient in Nitrolim. This fertilizer is significant as it helps in fixing nitrogen in the soil thereby promoting plant growth.

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Electronegativity is defined as an atom’s ability to attract an electron pair when forming a covalent bond. This property increases as you move left to right across the periodic table due to an increase in the nuclear charge’s attractive forces. It decreases as you move top to bottom, owing to the shielding effect of sub-levels and increased atomic radius, which makes electrons easier to remove. This culminates in Fluorine, being the highest and furthest to the right on the periodic table, hence it is the most electronegative.

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Froth and foams are examples of “gas suspended in liquid”. They are typically created when gas bubbles are dispersed in a liquid. This physical phenomenon is commonly observed in many daily life scenarios such as soap lather and carbonated drinks. Technically, they are a special case of colloid where little blobs of one liquid are dispersed in another and show the property of surface tension.

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Andesite is an igneous volcanic rock with intermediate composition and is not used as an ore. Chalcopyrite is a major copper ore, sphalerite is the primary ore of zinc, and cinnabar is the main ore of mercury. Andesite mainly consists of plagioclase, pyroxene, and amphibole minerals and forms in volcanic arcs associated with subduction zones.

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The sources of e-waste are faulty desktop computers, cables, printers, refrigerators, air conditioners, televisions, electronic and electrical devices. E-waste generated by the Mobile Phones are copper, silver, gold, palladium. Among them copper is found abundantly.

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The Contact Process is a method primarily used for preparing sulphuric acid on a large scale. It involves the oxidation of sulfur dioxide to sulfur trioxide in presence of a catalyst such as vanadium pentoxide. The subsequent hydration of sulfur trioxide produces sulphuric acid. The Contact Process allows the production of high concentrations of sulphuric acid under economically feasible conditions.

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24 carat gold is considered to be the purest form of gold but it is too soft to be made into jewellery. It is alloyed with metals like zinc, cadmium, silver or copper to make it hard.