Prepare the following microtubes Tube C 98 mu of water Tube

Prepare the following microtubes: Tube \"C\" 98 mu of water Tube \"D\" 975 mu i of water Add 2 mu of food coloring to Tube \"C\" Mix tube \"C\" and pipette 25 mu of mixture of \"C\" into tube \"D\" What is the final dilution of tube \"D\" (x: y) ?

Solution

Ans. Step 1: Add 2 µL of food colouring to tube C.

Final volume of tube C = 98 µL (water) + 2 µL (food colouring) = 100 µL

Current Dilution factor = Volume of food colouring taken / Final volume made upto

                        = 2 µL / 100 µL

                        = 0.02

Step 2: 25 µL of final C is added to tube D

Final volume of tube D = 975 µL (water) + 25 µL (tube C) = 1000 µL

Current dilution factor = Volume of C taken / Final volume made upto

                                    = 25 µL / 1000 µL

                                    = 0.025

Total dilution factor = Current dilution factor (step 2) x Previous dilution factor (of step 1)

                                    = 0.02 x 0.025

                                    = 0.0005

                                     = 5 : 10000

                                    = 5.0 x 10^-4

That is, the food colouring agent was diluted (5 : 10000) or 5 volume of it was diluted upto 10000 volumes.