The rusting of iron is accelerated by: MCQ with Answer and Explanation

The rusting of iron is accelerated by:
A. Presence of salt in water
B. Coating with paint
C. Dry air
D. Placing in vacuum
Answer: Option A
Solution (By JKSSB Mock Tests)
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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A solution with [H⁺] = 10⁻⁹ M has pH:
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B. 14
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Correct Answer: Option A


Explanation:
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Question #2
A substance has a melting point of -10°C and a boiling point of 50°C. At room temperature (25°C), it exists in which state?
A. Solid
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C. Gas
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Correct Answer: Option D


Explanation:
Since the room temperature (25°C) is between its melting point (-10°C) and boiling point (50°C), the substance exists in the liquid state. If the temperature were below -10°C, it would be solid, and above 50°C, it would be gas. This is based on standard phase transition principles.

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Question #3
Which of the following rays has the highest penetrating power?
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Correct Answer: Option A


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