Assertion (A): Ethene decolorizes bromine water. Reason (R): Ethene undergoes an addition reaction with bromine. MCQ with Answer and Explanation

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Assertion (A): Ethene decolorizes bromine water. Reason (R): Ethene undergoes an addition reaction with bromine.

A. A is false but R is true.

B. Both A and R are true but R is NOT the correct explanation of A.

C. Both A and R are true and R is the correct explanation of A.

D. A is true but R is false.

Answer: Option C

Solution (By JKExamLibrary)

Ethene (C2H4) is an alkene containing a reactive carbon-carbon double bond. When bromine water (brown) is added to ethene, the double bond breaks and bromine atoms add across it to form 1,2-dibromoethane (colorless). This addition reaction decolorizes the bromine water, serving as a test for unsaturation.

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If temperature of a gas is kept constant and pressure is doubled, volume becomes:

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Correct Answer: Option D

Explanation:
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Correct Answer: Option B

Explanation:
John Dalton put forward the atomic theory in 1808, proposing that matter is made of indivisible atoms, atoms of same element are identical, and compounds are combinations of atoms. Electron was discovered by J.J. Thomson, periodic table by Mendeleev, neutron by Chadwick.

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Graham's law deals with:

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Correct Answer: Option A

Explanation:
Graham's law of effusion/diffusion: Rate ∝ 1/√M (molar mass) at same temperature and pressure. Lighter gases diffuse faster. This is used in isotope separation (e.g., ²³⁵UF₆ vs ²³⁸UF₆) and in understanding gas behavior in leaks.

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