The valency of iron in Fe₂O₃ is: MCQ with Answer and Explanation

The valency of iron in Fe₂O₃ is:
A. 4
B. 1
C. 2
D. 3
Answer: Option D
Solution (By JKSSB Mock Tests)
In Fe₂O₃, oxygen has valency 2. Two Fe atoms combined with three O atoms: total negative charge = 6. For two Fe, total positive = 6, so each Fe has +3. Valency = 3 (ferric). In FeO, valency is 2 (ferrous).

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Correct Answer: Option C


Explanation:
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Question #2
The rate of diffusion of a gas is:
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B. Independent of its density.
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Correct Answer: Option D


Explanation:
Graham's Law of Diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of its density (or molar mass) at constant temperature and pressure (r ∝ 1/√d). Lighter gases diffuse faster than heavier ones, which explains why helium balloons deflate quickly.

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Hydrogen peroxide (H₂O₂) is commonly used as a:
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Correct Answer: Option B


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