Chemistry MCQs

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Bananas contain potassium-40, a radioactive isotope of potassium, which makes them slightly radioactive. The radiation is very minor and not dangerous at all to humans, but it is enough to trigger sensitive radiation sensors. The potassium provides bananas some of their nutritional benefits as well.

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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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Acid rain is caused by nitrous oxides (NOx) and sulfur dioxide (SO2) emissions, which react with water molecules in the atmosphere to form nitric and sulfuric acids. These acids then fall to the ground in rain, snow, fog, or dust particles.

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When Ozone is heated its volume will remain unchanged. It might change volume to an extent but not to a great extent.

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Cassiterite is a mineral that is a significant ore of tin. It is also known as tin oxide. Although rare, its key characteristic is its high specific gravity that makes it easy to separate it from other materials. Tin, which is extracted from Cassiterite, is commonly used in making alloys, punches, and cutting tools.

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Andesite is a type of volcanic rock that is intermediate in composition between basalt and rhyolite. It is typically gray to black in color and has a fine-grained, porphyritic texture, with larger crystals of feldspar and other minerals embedded in a finer-grained matrix. Andesite is formed when magma cools and solidifies at or near the Earth’s surface. It is common in volcanic arcs and other tectonically active areas, such as the Andes Mountains in South America, where it gets its name.
Andesite is typically less dense and more viscous than basalt, and it has a lower melting point. It is often intermediate in silica content between basalt and rhyolite, with a SiO2 content of around 53-62%. Andesite can also contain other minerals such as pyroxene, amphibole, and biotite, and it may exhibit a range of textural and compositional variations depending on the conditions under which it formed. Andesite is an important rock type in many geologic settings and is used in a variety of construction and landscaping applications.

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When quicklime (calcium oxide) is added to water, it reacts exothermically to form calcium hydroxide (slaked lime). This reaction produces heat and releases water vapor, which causes bubbling. The reaction can be represented as: [ ext{CaO} + ext{H}_2 ext{O}
ightarrow ext{Ca(OH)}_2 + ext{heat} ] Trivia: Quicklime is used in various applications, including steelmaking and water treatment, and was historically used in ancient construction.

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Chile saltpetre, or sodium nitrate (NaNO3), differs from regular saltpetre, which typically refers to potassium nitrate (KNO3). Chile saltpetre is primarily composed of sodium, while traditional saltpetre contains potassium. Historically, Chile saltpetre was extensively mined in the Atacama Desert and was crucial for fertilizer and explosives in the 19th century.

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Silica gel possesses hygroscopic properties, meaning it can absorb and hold water vapour. This makes it an effective desiccant or drying agent. When packaged with products, silica gel can help control humidity and prevent spoilage or degradation by absorbing excess moisture. This property is particularly valuable when shipping or storing items that can be negatively impacted by damp conditions, like electronics, food, and leather goods.

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Hydrogen chloride gas released from volcanic eruption is responsible for temporary acid rain in colder regions.