12. The molar absorption coefficient of the Ni2+ complex with dimethylglyoxil ne in solution at a wavelength of 445 nm is 14500. What is the minimum thickness can be used to determine nickel with an approximate concentration of 110^-6mol/1 if the minimum optical density recorded by the device is 0.01 ? Id, mA

To determine the minimum thickness of the solution required to measure nickel with an approximate concentration of $10^{-6} mol/L$, we can use the Beer-Lambert Law, which states that the optical density (OD) is directly proportional to the concentration of the solution.<br /><br />The Beer-Lambert Law is given by the equation:<br /><br />\[ OD = ε \cdot c \cdot l \]<br /><br />where:<br />- OD is the optical density,<br />- ε is the molar absorption coefficient,<br />- c is the concentration of the solution, and<br />- l is the thickness of the solution.<br /><br />Given that the molar absorption coefficient (ε) is 14500, the concentration (c) is $10^{-6} mol/L$, and the minimum optical density (OD) recorded by the device is 0.01, we can rearrange the equation to solve for the thickness (l):<br /><br />\[ l = \frac{OD}{ε \cdot c} \]<br /><br />Substituting the given values:<br /><br />\[ l = \frac{0.01}{14500 \cdot 10^{-6}} \]<br /><br />\[ l = 0.000692 \, cm \]<br /><br />Therefore, the minimum thickness of the solution required to determine nickel with an approximate concentration of $10^{-6} mol/L$ is 0.000692 cm.