Chapter 20.3, Problem 20.4P

(a)

Interpretation Introduction

Interpretation: The given conversion has to be carried out:

Concept Introduction:

$UV-$ spectroscopy :

• • $\text{UV-}$ spectroscopy is the technique that is widely used to characterize a compound via conjugation.
• • Conjugation between double bonds in a compound decreases the energy gap between filled and unfilled $\text{π}$-orbitals.
• • The smaller energy gap absorbs longer wavelength of ultraviolet radiation and effectively promotes the ${\text{π-π}}^{\text{*}}$ transition.
• • The longer wavelength of $\text{UV-}$ radiation can be easily observed in $\text{UV-}$ spectroscopy which corresponds to the particular ${\text{π-π}}^{\text{*}}$ transition of conjugation.
• • By this way, $\text{UV-}$ spectroscopy characterizes a compound with conjugation.

Example for the conversion of wavelength from $\text{μm}$ to $\text{nm}$ is shown here:

Let a wavelength has the value as x in the units of $\text{μm}$.

$\therefore \text{wavelength}=\text{x}\text{μm}$

$\begin{array}{c}\text{1}\text{μm}=1000\text{nm}\\ \frac{1000\text{nm}}{\text{1}\text{μm}}\times \text{x}\text{μm}\\ =\text{x}\times {10}^3\text{nm}\end{array}$

(b)

Interpretation Introduction

Interpretation: The given conversion has to be carried out:

Concept Introduction:

$UV-$ spectroscopy :

• • $\text{UV-}$ spectroscopy is the technique that is widely used to characterize a compound via conjugation.
• • Conjugation between double bonds in a compound decreases the energy gap between filled and unfilled $\text{π}$-orbitals.
• • The smaller energy gap absorbs longer wavelength of ultraviolet radiation and effectively promotes the ${\text{π-π}}^{\text{*}}$ transition.
• • The longer wavelength of $\text{UV-}$ radiation can be easily observed in $\text{UV-}$ spectroscopy which corresponds to the particular ${\text{π-π}}^{\text{*}}$ transition of conjugation.
• • By this way, $\text{UV-}$ spectroscopy characterizes a compound with conjugation.

Example for the conversion of wavelength from $\text{nm}$ to $\text{μm}$ is shown here:

Let a wavelength has the value as x in the units of $\text{nm}$.

$\therefore \text{wavelength}=\text{x}\text{nm}$

$\begin{array}{c}\text{1}\text{μm}=1000\text{nm}\\ \frac{\text{1}\text{μm}}{1000\text{nm}}\times \text{x}\text{nm}\\ =\text{x}\times {10}^{-3}\text{μm}\end{array}$