Dalton's Atomic theory could not explain which of the following? 

CONCEPT:

Dalton's Atomic Theory and Its Limitations

• Dalton's Atomic Theory proposed that:
  • All matter is made up of tiny, indivisible particles called atoms.
  • Atoms of the same element are identical in mass and properties.
  • Atoms of different elements combine in fixed ratios to form compounds (Law of Constant Proportion).
  • Atoms are neither created nor destroyed in chemical reactions (Law of Conservation of Mass).
• Limitations:
  • While Dalton's theory could explain many laws like the Law of Conservation of Mass and the Law of Constant Proportion, it failed to explain the Law of Gaseous Volume.
  • The Law of Gaseous Volume, proposed by Gay-Lussac, states that gases react in simple whole-number ratios by volume under the same conditions of temperature and pressure. This requires understanding molecular structures, which Dalton's theory did not address.

EXPLANATION:

• The Law of Gaseous Volume involves the concept of molecules and their behavior in the gaseous state. For example:
  • When hydrogen gas reacts with oxygen gas to form water vapor:

    2H₂(g) + O₂(g) → 2H₂O(g)

  • The volume ratio of hydrogen, oxygen, and water vapor is 2:1:2 under the same conditions.
• Dalton's Atomic Theory assumed atoms as indivisible and did not account for the existence of molecules or the behavior of gases in terms of volume. Thus, it could not explain Gay-Lussac's Law of Gaseous Volume.

Therefore, Dalton's Atomic Theory could not explain the Law of Gaseous Volume.