Statement - I : The mole fraction of argon in air is 0.95
Statement - II : Volume percentage of all noble gases in air is much greater than unity

Statement I is false because the mole fraction of argon in air is actually around 0.0093, or 0.93%, rather than 0.95. Air is a mixture of different gases, and the composition can vary slightly depending on factors such as altitude and location. However, argon is typically present in air at a concentration of less than 1%.

Statement II is false.

While noble gases are present in trace amounts in air, their combined volume percentage is actually less than unity. The noble gases, which include helium, neon, argon, krypton, and xenon, are all present in air at concentrations of less than 1%. Helium is the most abundant noble gas in air, with a concentration of around 5 ppm by volume, while the other noble gases have concentrations of less than 1 ppm. Therefore, the combined volume percentage of all the noble gases is less than 1%.