zero absorbance or $100\%.$ If not, adjust the spectrophotometer

accordingly.

$(2)$ Set the wavelength of the spectrophotometer to $400nm..$ Place the

stock solution $($Solution $5)$ in a cuvet following the "blank solution

procedure" as above. Measure and record the wavelength and

absorbance$.$ Scan the wavelength range of the spectrophotometer

while recording absorbance values. You will need to scan manually,

setting the absorbance at zero $(100\%T)$ with the blank solution

$MHN{O}_3)$ at EACH chosen wavelength before recording the

absorbance of the stock solution.

Plot the data, absorbance$,A(y-$axis$)$ versus the wavelength, $(x-$axis$),$

to determine the ${}_{\text{m}\text{a}\text{x}},$ the wavelength where maximum absorbance

occurs for the cobalt ion.