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Per NCERT, in Activity 9.2 with vinegar and baking soda, why did Experimental Set-up 1 show a DECREASE in final mass while Set-up 2 (sealed balloon) showed NO change?

AVinegar evaporated in Set-up 2
BMass was destroyed in Set-up 1
CThe weighing balance malfunctioned
DSet-up 1 allowed CO₂ gas to escape; Set-up 2 trapped the gas in the balloon — confirming mass is conserved when the system is closed
Answer & Solution
Correct answer: D. Set-up 1 allowed CO₂ gas to escape; Set-up 2 trapped the gas in the balloon — confirming mass is conserved when the system is closed
Per NCERT §9.1, gas escape in open systems gives apparent mass loss; sealed systems preserve total mass. The other options misstate.
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