Chapter 8, Problem 41PS

Which of the following molecules is(are) polar? For each polar molecule indicate the direction of polarity—that is, which is the negative end, and which is the positive end of the molecule.

1. (a) BeCl₂
2. (b) HBF₂
3. (c) CH₃Cl
4. (d) SO₃

Interpretation Introduction

Interpretation: Check whether the given molecule is polar or not. If the molecule is polar then the direction of polarity has to be indicated.

Concept Introduction:

Polar molecules are the molecules having a positive and negative end and so there will be a charge separation.

A polar molecule is a molecule where the polar bonds are asymmetrically arranged (the dipoles do not cancel)

A nonpolar molecule is a molecule with no polar bonds or a molecule where the polar bonds are symmetrically arranged.

In polar molecule the charge separation occurred with respect to the difference in electronegativity of atoms in the molecule.

Direction of dipole moment in a molecule is can be represented as follows,

Different types of molecules and their geometry in accordance with the VSEPR theory are mentioned below,

$\begin{array}{ccccc}\begin{array}{l}Typeof\\ Molecule\end{array}& \begin{array}{l}No.ofatoms\\ bondedtocentralatoms\end{array}& \begin{array}{l}No.oflonepairs\\ oncentralatom\end{array}& \begin{array}{l}Arrangementof\\ electronpairs\end{array}& \begin{array}{l}Molecular\\ Geometry\end{array}\\ A{B}_2& 2& 0& Linear& Linear\\ A{B}_3& 3& 0& Trigonalplanar& Trigonalplanar\\ A{B}_4& 4& 0& Tetrahedral& Tetrahedral\\ A{B}_5& 5& 0& Trigonalbipyramidal& Trigonalbipyramidal\\ A{B}_6& 6& 0& Octahedral& Octahedral\end{array}$

Explanation of Solution

${\text{BeCl}}_2$ is a linear molecule which means it is symmetric. And so this molecule is non-polar in nature because the bond dipoles cancel each other.

Interpretation Introduction

Interpretation: Check whether the given molecule is polar or not. If the molecule is polar then the direction of polarity has to be indicated.

Concept Introduction:

Polar molecules are the molecules having a positive and negative end and so there will be a charge separation.

A polar molecule is a molecule where the polar bonds are asymmetrically arranged (the dipoles do not cancel)

A nonpolar molecule is a molecule with no polar bonds or a molecule where the polar bonds are symmetrically arranged.

In polar molecule the charge separation occurred with respect to the difference in electronegativity of atoms in the molecule.

Direction of dipole moment in a molecule is can be represented as follows,

Different types of molecules and their geometry in accordance with the VSEPR theory are mentioned below,

$\begin{array}{ccccc}\begin{array}{l}Typeof\\ Molecule\end{array}& \begin{array}{l}No.ofatoms\\ bondedtocentralatoms\end{array}& \begin{array}{l}No.oflonepairs\\ oncentralatom\end{array}& \begin{array}{l}Arrangementof\\ electronpairs\end{array}& \begin{array}{l}Molecular\\ Geometry\end{array}\\ A{B}_2& 2& 0& Linear& Linear\\ A{B}_3& 3& 0& Trigonalplanar& Trigonalplanar\\ A{B}_4& 4& 0& Tetrahedral& Tetrahedral\\ A{B}_5& 5& 0& Trigonalbipyramidal& Trigonalbipyramidal\\ A{B}_6& 6& 0& Octahedral& Octahedral\end{array}$

Explanation of Solution

The structure of $HB{F}_2$ is,

This molecule has a trigonal planar geometry. The fluorine atoms occupied on the negative end of the dipole and the hydrogen atom on the positive end.

Thus,

$HB{F}_2$ is an asymmetric molecule. And so this molecule is polar in nature because the bond dipoles do not cancel each other.

Interpretation Introduction

Interpretation: Check whether the given molecule is polar or not. If the molecule is polar then the direction of polarity has to be indicated.

Concept Introduction:

Polar molecules are the molecules having a positive and negative end (dipole) and so there will be a charge separation.

A polar molecule is a molecule where the polar bonds are asymmetrically arranged (the dipoles do not cancel)

A nonpolar molecule is a molecule with no polar bonds or a molecule where the polar bonds are symmetrically arranged.

In polar molecule the charge separation occurred with respect to the difference in electronegativity of atoms in the molecule.

Direction of dipole in a molecule is can be represented as follows,

Different types of molecules and their geometry in accordance with the VSEPR theory are mentioned below,

$\begin{array}{ccccc}\begin{array}{l}Typeof\\ Molecule\end{array}& \begin{array}{l}No.ofatoms\\ bondedtocentralatoms\end{array}& \begin{array}{l}No.oflonepairs\\ oncentralatom\end{array}& \begin{array}{l}Arrangementof\\ electronpairs\end{array}& \begin{array}{l}Molecular\\ Geometry\end{array}\\ A{B}_2& 2& 0& Linear& Linear\\ A{B}_3& 3& 0& Trigonalplanar& Trigonalplanar\\ A{B}_4& 4& 0& Tetrahedral& Tetrahedral\\ A{B}_5& 5& 0& Trigonalbipyramidal& Trigonalbipyramidal\\ A{B}_6& 6& 0& Octahedral& Octahedral\end{array}$

Explanation of Solution

The structure of $C{H}_{3}Cl$ is,

This molecule has a tetrahedral geometry. The chlorine atom occupied on the negative end of the dipole and the hydrogen atom on the positive end.

Thus,

$C{H}_{3}Cl$ is an asymmetric molecule. And so this molecule is polar in nature because the bond dipoles do not cancel each other.

Interpretation Introduction

Interpretation: Check whether the given molecule is polar or not. If the molecule is polar then the direction of polarity has to be indicated.

Concept Introduction:

Polar molecules are the molecules having a positive and negative end and so there will be a charge separation.

A polar molecule is a molecule where the polar bonds are asymmetrically arranged (the dipoles do not cancel)

A nonpolar molecule is a molecule with no polar bonds or a molecule where the polar bonds are symmetrically arranged.

In polar molecule the charge separation occurred with respect to the difference in electronegativity of atoms in the molecule.

Direction of dipole moment in a molecule is can be represented as follows,

Different types of molecules and their geometry in accordance with the VSEPR theory are mentioned below,

$\begin{array}{ccccc}\begin{array}{l}Typeof\\ Molecule\end{array}& \begin{array}{l}No.ofatoms\\ bondedtocentralatoms\end{array}& \begin{array}{l}No.oflonepairs\\ oncentralatom\end{array}& \begin{array}{l}Arrangementof\\ electronpairs\end{array}& \begin{array}{l}Molecular\\ Geometry\end{array}\\ A{B}_2& 2& 0& Linear& Linear\\ A{B}_3& 3& 0& Trigonalplanar& Trigonalplanar\\ A{B}_4& 4& 0& Tetrahedral& Tetrahedral\\ A{B}_5& 5& 0& Trigonalbipyramidal& Trigonalbipyramidal\\ A{B}_6& 6& 0& Octahedral& Octahedral\end{array}$

Explanation of Solution

The structure of $S{O}_3$ is,

This molecule has trigonal planer geometry. The direction dipole moment in the molecule is represented below,

Thus,

However $S{O}_3$ an asymmetric molecule it is non- polar in nature because the bond dipoles cancel each other.