Chapter 3, Problem 65IP

(a)

Interpretation Introduction

Interpretation:

Expected structure (5) has to be drawn; mechanism for the formation of structure (5) from structure (3) has to be drawn.

Concept Introduction:

Lewis acid: A compound or ionic species which can accept an electron pair from a donor compound.

Lewis base: A compound or ionic species which can donate an electron pair to an acceptor compound.

Curved arrows: Curved arrows are used to show the direction of electrons movement. It has a tail (the source of electrons, usually lone pair or bonding pair from a sigma or pi-bond) and head (the destination of electrons, usually forming new lone pair on atom or a new bond). Electrons always flow from high electron density to low electron density.

(b)

Interpretation Introduction

Interpretation:

For the given transformation, given base is an appropriate base has to be verified with ${\text{pK}}_{\text{a}}$ values.

Concept Introduction:

Using $p{K}_a$values to compare Acidity: In general, acid-base reaction said to reach equilibrium; the position of equilibrium is described by the term $K_{eq}$. When an acid-base reaction is carried out in aqueous solution, the new term arrives by the term $K_a$.

$p{K}_a=-log{K}_a$

$p{K}_a$ Values are used as measure of acidity; a strong acid will have a low $p{K}_a$ and a weak acid will have a high $p{K}_a$.

Using $p{K}_a$values to compare Basicity: $p{K}_a$ Values are also used to compare bases; by drawing the conjugate acid of each base and compare the $p{K}_a$ values and identify the stronger base.

(c)

Interpretation Introduction

Interpretation:

Using IR spectroscopy, the conversion of structure (1) to (5) has to be verified.

Concept Introduction:

IR spectral studies: It is a spectroscopic technique which is used to determine the functional groups present in the given compound sample by absorbing frequency in particular range with respect to the group present in the given sample.

Wavenumber: It is defined as the number of waves in one centimeter. The wavenumber indicates the location of each signal with respect to the functional group in the molecule and its unit is ${\text{cm}}^{\text{-1}}$.