Question

10 drops of an oleic acid solution of concentration 1 by 400 cm cube per centimetre cube alcohol are dropped on water surface the circular film does produced has radius 10 cm find the molecular size of oleic acid if the radius of each drop is 1.4 mm

Answer 1

Hi....

The drop has radius,r =1.4mm
volume=4/3*(pi)*r3
and we know the concentration=1/400 cm3/m3
so calculate the number of the molecules of oleic acid in this 10 drops.These molecules have formed the circular surface of area =2*(pi)*10cm
Now we know the radius of the circle and so calculate the area of the circle.
Divide this area by the number of molecules to get the molecular size of the oleic acid..


Hope this helps u!!

Answer 2

Hi.....hope this helps you.......