Solution:
Mass of a drop of water = 0.0018g
Moles of water
Number of water molecules in one drop = 10-4 NA
Number of water molecules in two drops
The volume of a drop of water is 0.0018 mL then the number of water molecules present in two drop of water at room temperature is:
Mass of a drop of water = 0.0018g
Moles of water
Number of water molecules in one drop = 10-4 NA
Number of water molecules in two drops