Question

If a 0.135 M solution of CO2+ has an absorbance of 0.350, what is the concentration of a solution with an absorbance of 0.435

Answer 1

Answer – We are given, concentration of [Co²⁺] = 0.135 M , A = 0.350

[Co²⁺] = ?, A = 0.435, the pathlength cell = 1.0 cm

We know the Beer’s law –

A = ε*l*C

So, ε = A/l*C

         = 0.350 / 0.135 M.1 cm

         = 2.59 M^-1cm^-1

Now at absorbance, A = 0.435

C = A / ε*l

    = 0.435 / 2.59 M^-1cm^-1 *1 cm

    = 0.168 M

the concentration of a solution with an absorbance of 0.435 is 0.168 M