Hydrogen peroxide acts as an oxidizing agent in which reaction?
A. H₂O₂ + O₃ → H₂O + 2O₂
B. H₂O₂ + Ag₂O → 2Ag + H₂O + O₂
C. H₂O₂ + PbS → PbSO₄ + H₂O
D. H₂O₂ + 2KI + H₂SO₄ → I₂ + K₂SO₄ + 2H₂O
Answer: Option C
Solution (By JKSSB Mock Tests)
In reaction C, H₂O₂ oxidizes PbS (black) to PbSO₄ (white), where oxygen atoms from H₂O₂ are added. H₂O₂ itself is reduced to H₂O. In reaction D, H₂O₂ oxidizes I⁻ to I₂; that is also oxidation. But the most straightforward oxidizing reaction among these is the restoration of old paintings (PbS → PbSO₄). Reaction A: H₂O₂ reduces O₃ (acts as reducing agent). Reaction B: H₂O₂ reduces Ag₂O. H₂O₂ can act as both oxidizing and reducing agent.
Explanation:
Methanol (CH₃OH) contains the hydroxyl (–OH) functional group characteristic of alcohols. It is the simplest alcohol, also called wood alcohol. Ethanol (C₂H₅OH) is the alcohol in beverages. Aldehydes have –CHO group, ketones have >C=O, carboxylic acids have –COOH. Methanol is toxic; ingestion can cause blindness or death. It is used as a solvent and in formaldehyde production.
Explanation:
Manganese is extracted by the aluminothermic process (Goldschmidt thermite process) where Mn₃O₄ is reduced by aluminium: 3Mn₃O₄ + 8Al → 9Mn + 4Al₂O₃. This works for metals with less reactivity than Al but not too reactive. Sodium is extracted by electrolysis. Iron is extracted by smelting with coke. Zinc by carbon reduction/electrolysis.
Explanation:
Boyle's law: P₁V₁ = P₂V₂. So P₂ = P₁(V₁/V₂) = P₁(10/20) = P₁/2. Pressure is halved. If volume doubles, pressure halves, assuming constant temperature and amount. This is an inverse relationship.
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