Answer: -
H₂ will diffuse the fastest.
Explanation: -
According to Graham's Law of Diffusion
The rate of diffusion is inversely proportional to the square root of it's density or molar mass. So the lower the molar mass faster the rate of diffusion.
Molar mass of Ne = 20 g / mol
Molar mass of CH₄ = 12 x 1 + 1 x 4 = 16 g /mol
Molar mass of Ar = 40g / mol
Molar mass of H₂ = 1 x 2 = 2 g / mol
Thus H₂ will diffuse the fastest.
The one u clicked is the the right one
825.5mL
To find this, use the equation 
= 
Make sure to convert all temperatures in Celsius to Kelvin by adding 273. Once you do that, multiply and divide accordingly to get the final answer of 825.5mL
Hope this helps!
Answer:
Chagrin River or cold water
