Rubber is made more strong and elastic by the process of:
A. Vulcanization
B. Fermentation
C. Saponification
D. Hydrogenation
Answer: Option A
Solution (By JKSSB Mock Tests)
Vulcanization involves heating natural rubber with sulfur, forming cross-links between polymer chains. This improves elasticity, tensile strength, and resistance to temperature changes. Hydrogenation adds H₂, saponification makes soap, fermentation produces alcohol.
Explanation:
Lead-acid battery uses dilute sulfuric acid (H₂SO₄) as the electrolyte with lead dioxide (PbO₂) as positive plate and spongy lead (Pb) as negative plate. Discharge reaction: Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O. It is a secondary (rechargeable) battery used in automobiles. The specific gravity of electrolyte indicates the state of charge. KOH is used in Ni-Cd and alkaline batteries.
Explanation:
Cracking is a petrochemical process where complex, heavy hydrocarbon molecules are broken down (cleaved) into lighter, more valuable molecules like gasoline and alkenes. This is achieved by applying high temperatures and pressures, often in the presence of a catalyst (catalytic cracking).
Explanation:
Temporary hardness is due to dissolved bicarbonates of Ca and Mg. These can be removed by boiling, which precipitates carbonates. Calcium sulfate and chloride cause permanent hardness. Sodium chloride does not cause hardness. Boiling: Ca(HCO₃)₂ → CaCO₃↓ + H₂O + CO₂. Bicarbonates are formed when water containing CO₂ passes over limestone.
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