18. The density of rubbing alcohol is .789 g/ml. What is the mass of rubbing alcohol in a 500-ml bottle of rubbing alcohol?

The number of   milliliters  of  isopropyl alcohol that are  in   a 400 ml bottle  of this solution  is 280 Ml

Explanation:

% V/V =  volume of  solute/ volume  of  solution  x 100

Let the volume  of solute  be =  y  ml

the volume  of  solution =  400 ml

convert 70%  to fraction = 70/100

by  substituting  the value  in the equation

= y  ml/  400 ml =  70/100

by cross  multiplication

100y =400 x70

100y=  28000

y= 280 ml

c) should be the answer.