The dilution factor : 100
The dilution factor(DF) : ratio of concentration of stock solution and diluted solution or ratio of the volume of final solution to the initial volume from stock solution
From equation of dilution :
M₁V₁=M₂V₂
[tex]\tt DF=\dfrac{M_1}{M_2}=\dfrac{V_2}{V_1}[/tex]
Volume of aliquot = 0.1 ml
Volume of diluent = 9.9 ml
So final volume :
[tex]\tt V_f(final~volume)=volume~aliquot+volume~diluent\\\\V_f=0.1+9.9=10~ml[/tex]
The dilution factor (DF) :
[tex]\tt D_f=\dfrac{V_f}{V_i}\\\\D_f=\dfrac{10}{0.1}=100[/tex]