Raindrops have an average size of 1 mm when it is formed at the upper atmosphere. Why the velocity of the raindrop is uniform?

Raindrops falling due to gravity do not acquire high velocity. Define the velocity of the raindrop when unbalanced force on it is zero.

The liquids X and Y form an ideal solution . The mixture has a vapour pressure of 400 mm at 300 K when mixed in the molar ratio of 1: 1 and a vapour pressure of 350 mm when mixed in the molar ratio of 1:2 at the same temperature . The vapour pressures of the two pure liquids X and Y respectively are