Chapter 16, Problem 125SCQ

(a)

Interpretation Introduction

Interpretation:

The electron dot structure of $\left({\text{I}}_3{}^{-}\right)$ has to be drawn.

Concept Introduction:

Valence electrons are represented by dots placed around the chemical symbol.  The valance electrons are placed around the elements (atoms) maximum electrons can fill around the atom. First fill the single electron around the atom and paired the electrons.

The valance electron for iodine atom is seven. Total valence electrons in triiodide anion are counted and electron dot structure for the anion is written. When iodine $\left({\text{I}}_{\text{2}}\right)$ is mixed in an aqueous solution of potassium iodide $\left(\text{KI}\right)$, an acid-base reaction occurs. Iodide anion $\left({\text{I}}^{-}\right)$ from potassium iodide acts as a Lewis base and iodine $\left({\text{I}}_{\text{2}}\right)$ acts as a Lewis acid.

(b)

Interpretation Introduction

Interpretation:

The chemical reaction has to be written by indicating the Lewis acid and Lewis base.

Concept Introduction:

Lewis definition:

A Lewis acid is a substance that can accept and share an electron pair.

A Lewis base is a substance that can donate and share an electron pair.