A solution of a specific vitamin has a λ max of 275 nm and a concentration of 6.18 × 10 − 7 M . The absorbance of the solution at 275 nm is A = 0.165 . What is the molar absorptivity of the vitamin at 275 nm ? A sample path length is 1.00 cm .

2.67 × 10⁵ cm⁻¹ M⁻¹

Explanation:

We can relate the absorbance of a solution (A) with the concentration of the analyte (c) using Beer-Lambert law.

A = ε × l × c

where,

ε: molar absorptivity of the vitamin

l: the optical path length

A = ε × l × c

ε = A / l × c

ε = 0.165 / 1.00 cm × 6.18 × 10⁻⁷ M

ε = 2.67 × 10⁵ cm⁻¹ M⁻¹

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.