Question

Suppose that you have a solution in a cell of length 1 cm. The measuring absorbance of this solution at a particular wavelength is 1.92. What is the molar absorptivity of this solution. Knowing that its conc .is 9.90x 10- 5 M.

Answer 1

Answer : The molar absorptivity of this solution is, $1.93\times 10^{4}M^{-1}cm^{-1}$

Solution :

Using Beer-Lambert's law :

Formula used :

$A=\epsilon \times C\times l$

where,

A = absorbance of solution = 1.92

C = concentration of solution = $9.90\times 10^{-5}M$

l = length of the cell = 1 cm

$\epsilon$ = molar absorptivity of this solution = ?

Now put all the given values in the above formula, we get the molar absorptivity of this solution.

$1.92=\epsilon \times (9.90\times 10^{-5}M)\times (1cm)$

$\epsilon=1.93\times 10^{4}M^{-1}cm^{-1}$

Therefore, the molar absorptivity of this solution is, $1.93\times 10^{4}M^{-1}cm^{-1}$