you have 20% sucrose solution. you need to mke 100ml of 15% sucrose solution. which is the correct dilution?

Question

A. 85ml of 20% sucrose and 15ml of h2o
B. 25ml of 20% sucrose and 75ml of h2o
C. 75ml of 20% sucrose and 25ml of h2o
D. 15ml of 20% sucrose and 85ml of h2o

Answer 1

c1v1 = c2v2
c = concn
v = volume
20*v = 15*100
v = ? of the 20%.
If you want to get picky this won't do it. It isn't 25 mL of the 20% + 75 mL H2O; it is 25 mL of the 20% plus enough water to make 100 mL.