Question

What was Avogadro’s hypothesis? On whose work was it based?

Answer 1

Avogadro’s hypothesis (1811) states that equal volumes of gases, at the same temperature and pressure, contain equal numbers of molecules. From this he distinguished atoms from molecules and inferred that many elemental gases are diatomic (e.g., H2, O2), which made it possible to deduce correct molecular formulas and relative molecular masses.

Avogadro’s idea was motivated by and intended to reconcile John Dalton’s atomic theory with Joseph-Louis Gay-Lussac’s experimental law of combining volumes (the observation that gases combine in simple whole-number volume ratios).