Which of the following metals is stored under kerosene?
A. Copper
B. Zinc
C. Iron
D. Sodium
Answer: Option D
Solution (By JKExamLibrary)
Sodium reacts vigorously with moisture and oxygen in air, so it is stored under kerosene to prevent contact. Potassium, lithium are similarly stored. Iron, zinc, copper do not require such storage.
Explanation:
Pure rainwater naturally has pH about 5.6 because CO₂ from air dissolves and forms carbonic acid. This is not considered acid rain. Acid rain has pH below 5.0 (due to SO₂ and NOₓ).
Explanation:
Salt (NaCl) dissolved in water increases the electrical conductivity of the electrolyte, facilitating the electrochemical corrosion process. This is why iron rusts faster in coastal areas and on roads treated with deicing salts. Dry air prevents rusting (needs moisture). Coating with paint blocks oxygen and moisture. Vacuum has no oxygen.
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