Assertion :According to Dobernier's, a group of three similar elements arranged in their increasing atomic weights show that atomic weight of middle is equal to the arithmetic mean of the other two elements. Reason: Atomic weight is equal to one twelfth of mass of a carbon atom.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

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Assertion is correct but Reason is incorrect

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Assertion is incorrect but Reason is correct

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Solution

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
According to Dobernier's, a group of three similar elements arranged in their increasing atomic weights show that atomic weight of middle is equal to the arithmetic mean of the other two elements. But according to the modern concepts atomic weight is equal to one-twelfth of the mass of a carbon atom.a
Thus both assertion and reason are correct but the reason is not the correct explanation of assertion.

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