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Per NCERT, when zinc reacts with dilute HCl to form zinc chloride + hydrogen gas, would conservation of mass be observed in an OPEN container — and why?
ANo — H₂ gas escapes from the open container, so the final mass would appear LOWER than the initial mass (though mass is actually conserved if gas were collected)
BNo, because reactions break mass conservation
CYes, because H₂ has zero mass
DYes — mass is always conserved even with gas escape
Answer & Solution
Correct answer: A. No — H₂ gas escapes from the open container, so the final mass would appear LOWER than the initial mass (though mass is actually conserved if gas were collected)
Per NCERT §9.1 Think as a Scientist, gas escape in open systems gives apparent mass loss. To verify the law, the gas must be collected (closed system).
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