Chapter 21, Problem 97IL

(a)

Interpretation Introduction

Interpretation: To predict the formula for unknown bromine oxide A in the given reaction.

Concept introduction: An oxide of bromine ${\text{BrO}}_{\text{2}}$ is prepared by treating bromine with ozone. However, it was later observed that the heating of this oxide results in formation of two more oxides which can be identifed using reagents like sodium iodide and silver nitrate. The structure of these oxides can be either linear or bent.

(b)

Interpretation Introduction

Interpretation: To draw the Lewis structure for A  and ${\text{Br}}_{\text{2}}\text{O}$. Molecular geometry of these compounds has to be speculated.

Concept introduction:

An oxide of bromine ${\text{BrO}}_{\text{2}}$ is prepared by treating bromine with ozone. However, it was later observed that the heating of this oxide results in formation of two more oxides which can be identifed using reagents like sodium iodide and silver nitrate. The structure of these oxides can be either linear or bent.

Lewis structures are diagrams that represent the chemical bonding of covalently bonded molecules and coordination compounds.

It is also known as Lewis dot structures which represent the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.

Molecular geometry is the shape of a molecule predicted by considering only bond pair of electrons

According to VSEPR theory, the geometry is predicted by the minimizing the repulsions between electron-pairs in the bonds and lone-pairs of electrons. The VSEPR theory is summarized in the given table as,

$\begin{array}{cccc}\text{Electron-pair}& \text{lone-pair}& \text{Electron-pair}\text{geometry}& \text{Molecular}\text{shape}\\ 2& 0& \text{Linear}& \text{Linear}\\ 3& 0& \text{Trigonal}\text{planar}& \text{Trigonal}\text{planar}\\ 2& 1& \text{Trigonal}\text{planar}& \text{Bent}\\ 4& 0& \text{Tetrahedral}& \text{Tetrahedral}\\ 3& 1& \text{Tetrahedral}& \text{Pyramidal}\\ 2& 2& \text{Tetrahedral}& \text{V}-\text{shape}\\ 5& 0& \text{Trigonal}\text{bipyramidal}& \text{Trigonal}\text{bipyramidal}\\ 4& 1& \text{Trigonal}\text{bipyramidal}& \text{See}-\text{saw}\\ 3& 2& \text{Trigonal}\text{bipyramidal}& \text{T}-\text{shape}\\ 2& 3& \text{Trigonal}\text{bipyramidal}& \text{Linear}\\ 6& 0& \text{Octahedral}& \text{Octahedral}\\ 5& 1& \text{Octahedral}& \text{Square}\text{pyramidal}\\ 4& 2& \text{Octahedral}& \text{Square}\text{planar}\end{array}$