Which of the following metals is preserved in kerosene oil?
A. Calcium
B. Magnesium
C. Sodium
D. Iron
Answer: Option C
Solution (By JKExamLibrary)
Sodium and potassium are highly reactive alkali metals that react vigorously with oxygen and moisture in the air, potentially catching fire. To prevent accidental fires, they are stored immersed in kerosene oil. Magnesium and calcium do not require such extreme storage conditions.
Explanation:
Metals are malleable (can be beaten into sheets), ductile (drawn into wires), and good conductors. Brittleness is a characteristic of non-metals and some metalloids; metals can deform without breaking. For example, gold is highly malleable.
Explanation:
At anode (oxidation): 2Cl⁻ → Cl₂ + 2e⁻ (chlorine gas). At cathode (reduction): Na⁺ + e⁻ → Na (liquid sodium). In aqueous NaCl, due to water, cathode produces H₂ and anode Cl₂ (or O₂ depending on concentration).
Explanation:
Natural rubber (cis-1,4-polyisoprene) is an addition polymer of isoprene (2-methyl-1,3-butadiene). It is obtained from latex of rubber tree (Hevea brasiliensis). It is elastic but weak. Vulcanization with sulfur introduces cross-links, improving strength and elasticity. Ethene gives polyethylene; styrene gives polystyrene; vinyl chloride gives PVC.
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