Chemistry - Mole Concept Question with Solution | TestHub

ChemistryMole ConceptLaws of Chemical CalculationsMedium2 minQB
ChemistryMediumsingle choice

The following statements are given for different laws of chemical combination. Which of the following statement(s) is/are correct?

1. Gay-Lussac's law of gaseous volumes is valid only for ideal gases under all conditions.

2. The law of conservation of mass is valid only for reactions carried out in a closed container and not in an open container.

3. The same volume of nitrogen at STP combines with two different volumes of oxygen at STP to form NO₂ and N₂O₄.

4. A fixed mass of iron can combine with different masses of oxygen under different conditions.

Options:

Answer:
D
Solution:
  1. False. Gay-Lussac's law holds for gases measured at the same temperature and pressure; it is not limited to ideal gases or valid under all conditions.
  2. False. The law of conservation of mass applies to all reactions except nuclear reactions, in open or closed containers.
  3. False. N₂ + 2O₂ → 2NO₂ and N₂ + 2O₂ → N₂O₄: in both, N₂ : O₂ = 1 : 2 by volume (same T and P). So the same volume of nitrogen combines with the same volume of oxygen in both, not with two different volumes.
  4. True. Iron forms FeO and Fe₂O₃, so a fixed mass of iron combines with different masses of oxygen (law of multiple proportions).

So only statement 4 is correct: option D.

Stream:JEESubject:ChemistryTopic:Mole ConceptSubtopic:Laws of Chemical Calculations
⏱ 2mℹ️ Source: QB

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