Why is the rate of diffusion faster in the gaseous state?

$CO_{2}$ is a gas. Write any two of its gaseous properties to justify this. How can we liquefy this gas? Solid $CO_{2}$ is also known as dry ice. Why?

How do the following factors affect the rate of evaporation of a liquid?
$(a)$ Surface area
$(b)$ Temperature
$(c)$ Humidity

What is the effect of the following on the rate of diffusion?
$(i)$ Temperature
$(ii)$ Density of liquid

Why does the temperature of a substance remain constant during its melting point or boiling point?

The boiling points of diethyl ether, acetone, and $n-$butyl alcohol are $35\,^\circ\text{C}$, $56\,^\circ\text{C}$, and $118\,^\circ\text{C}$ respectively. Which one of the following correctly represents their boiling points in the Kelvin scale?