We know that
[tex]1ppb=0.00001 g/L[/tex]
therefore
[tex]15ppb = 0.000015 g/L[/tex]
the molar mass of chlorobenzene is 112.56
therefore moles of chlorobenzne in 15ppb will be:
[tex]moles_{chlorobenzene}=\frac{mass}{molarmass}=\frac{0.000015 g}{112.56}=1.33X10^{-7}[/tex]
Molarity is number of moles of solute dissolved in one litre of solution
The molarity will be thus
[tex]\frac{1.33X10^{-7}mol}{1L}[/tex]
[tex]molarity=1.33X10^{-7}mol/L[/tex]
