You have a stock solution tube A You transfer 05 ml stock in

You have a stock solution (tube A). You transfer 0.5 ml stock into a tube with 19.5 ml H2O (tube B). After mixing, you transfer 2 ml from tube B into a tube with 28 ml H2O (tube C). What is the cumulative dilution factor in this series? Be sure to show your work. Use diagrams where they would be helpful.

Solution

Dilution factor = Total volume/smple volume

In first dilution,

sample volume is 0.5ml

Total volume is 0.5 ml + 19.5 ml= 20ml

So, DF = 20/0.5 = 40

In the second step, 2ml of mixed sample from first dilution of dilution factor 40 is added to 28ml H2O.

Here, DF= 40*(30/2)

= 40*15

= 2.6

Hence,

Dilution factor in tube-A is 40

Dilution factor in tube-B is 2.66