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A fixed volume of a '20 volumes' H2O2 solution is diluted so that the total volume of the resulting solution becomes exactly twice the original volume. Which of the following statements is correct?

1. The volume strength of the diluted solution becomes '40 volumes'
2. The molarity of the solution becomes half of its initial molarity
3. The molality of the solution becomes half of its initial molality
4. The maximum amount of O2 gas obtainable from the solution remains the same

Correct answer: The maximum amount of O2 gas obtainable from the solution remains the same

Solution

When the solution is diluted to double its volume, the moles of H2O2 remain unchanged (no H2O2 is consumed), so the total O2 obtainable from decomposition is conserved. Volume strength halves (to 10 volumes, not 40). Molarity halves (correct). Molality does not exactly halve. The unambiguously and always correct statement among the options is D.

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