Question

6. An aqueous solution containing the [Cu(NH3)4]? complex ion was analyzed at 580 nm using a Spectre Vis spectrophotometer and a cuvette with a 1.0 cm path length. The absorbance of the solution was 0.301. If the equation of the line for the calibration plot of [Cu(NH)} at 580 nm is y = 56.0x +0.0081, what is the concentration of [Cu(NH3)4] in the solution?

Answer 1

The calibration plot for the absorbance of is constructed by plotting absorbance in y axis and concentration in x axis.

Cu(NH3)412+

The calibration equation of line taken at 580 nm is

y = 56.0.1 +0.0081

Where

y is the absorbance

x is the concentration.

Now, for an aqueous solution, the absorbance is 0.301 at 580 nm.

Hence, we can calculate the concentration of the aqueous solution of by putting y = 0.301 and solving for concentration x in the equation of the line.

Cu(NH3)412+

Hence,

y = 56.0.1 +0.0081 0.301 = 56.0.1 +0.0081 56.00 = 0.301 – 0.0081 0.301 – 0.0081 - 0.00523 56,0 r=-

Hence, the concentration of
Cu(NH3)412+
in the solution is approximately
0,00523 M
.