Which of the following is an example of oxidation?
A. Cl₂ + 2e⁻ → 2Cl⁻
B. 2H⁺ + 2e⁻ → H₂
C. Cu²⁺ + 2e⁻ → Cu
D. Na → Na⁺ + e⁻
Answer: Option D
Solution (By JKExamLibrary)
Oxidation is loss of electrons. Na loses an electron to become Na⁺, so it is oxidized. Options A, C, D involve gain of electrons (reduction). Oxidation also can be defined as gain of oxygen or loss of hydrogen. In the reaction, Na acts as reducing agent. Mnemonic: LEO (Loss of Electrons is Oxidation) GER (Gain of Electrons is Reduction).
Explanation:
Charles' law: V ∝ T (Kelvin) at constant P and n. V/T = constant. This means if temperature is doubled (in Kelvin), volume doubles. Temperature must be in Kelvin (K = °C + 273). Graph of V vs T is a straight line passing through origin. This law is used in hot air balloons: heated air expands, decreasing density, providing lift. Combined with Boyle's law gives PV = nRT.
Explanation:
Brass: Cu + Zn. Bronze: Cu + Sn. Steel: Fe + C. Duralumin: Al + Cu + Mg + Mn. Brass is corrosion-resistant and used in plumbing, musical instruments. Zinc content varies (5-45%). Brass with higher zinc is stronger but less ductile. Some brasses contain small amounts of other elements.
Explanation:
Fermentation is the anaerobic breakdown of glucose by enzymes (zymase) in yeast to produce ethanol and CO₂: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂. Esterification forms esters, saponification makes soap, hydrogenation adds H₂.
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