Answer : The concentration of a solution with an absorbance of 0.420 is, 0.162 M
Explanation :
Using Beer-Lambert's law :
[tex]A=\epsilon \times C\times l[/tex]
As per question, at constant path-length there is a direct relation between absorbance and concentration.
[tex]\frac{A_1}{A_2}=\frac{C_1}{C_2}[/tex]
where,
A = absorbance of solution
C = concentration of solution
l = path length
[tex]A_1[/tex] = initial absorbance = 0.350
[tex]A_2[/tex] = final absorbance = 0.420
[tex]C_1[/tex] = initial concentration = 0.135 M
[tex]C_2[/tex] = final concentration = ?
Now put all the given value in the above relation, we get:
[tex]\frac{0.350}{0.420}=\frac{0.135}{C_2}[/tex]
[tex]C_2=0.162M[/tex]
Thus, the concentration of a solution with an absorbance of 0.420 is, 0.162 M